Difference between revisions of "VirtualBox"

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(→‎Installation in EFI mode: Moving my additions to the EFISTUB page.)
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* Boot directly from the ESP partition using a [[EFISTUB#Using a startup.nsh script|startup.nsh script]].  
* Boot directly from the ESP partition using a [[EFISTUB#Using a startup.nsh script|startup.nsh script]].  
Do not bother with the VirtualBox Boot Manager (accessible with {{ic|F2}} at boot), as it is buggy and incomplete.It doesn´t store efivars set interactively. Therefore, EFI entries added to it manually in the fir(accessed with {{ic|F12}} at boot time) or with {{Pkg|efibootmgr}} will persist after a reboot [https://www.virtualbox.org/ticket/11177 but are lost when the VM is shut down].
Do not bother with the VirtualBox Boot Manager (accessible with {{ic|F2}} at boot), as it is buggy and incomplete. It doesn't store efivars set interactively. Therefore, EFI entries added to it manually in the firmware (accessed with {{ic|F12}} at boot time) or with {{Pkg|efibootmgr}} will persist after a reboot [https://www.virtualbox.org/ticket/11177 but are lost when the VM is shut down].
See also [https://bbs.archlinux.org/viewtopic.php?id=158003 UEFI Virtualbox installation boot problems].
See also [https://bbs.archlinux.org/viewtopic.php?id=158003 UEFI Virtualbox installation boot problems].

Revision as of 13:31, 9 April 2017

VirtualBox is a hypervisor used to run operating systems in a special environment, called a virtual machine, on top of the existing operating system. VirtualBox is in constant development and new features are implemented continuously. It comes with a Qt GUI interface, as well as headless and SDL command-line tools for managing and running virtual machines.

In order to integrate functions of the host system to the guests, including shared folders and clipboard, video acceleration and a seamless window integration mode, guest additions are provided for some guest operating systems.


Installation steps for Arch Linux hosts

In order to launch VirtualBox virtual machines on your Arch Linux box, follow these installation steps.

Install the core packages

Install the virtualbox package. You will need to choose a package to provide host modules:

To compile the virtualbox modules provided by virtualbox-host-dkms, it will also be necessary to install the appropriate headers package(s) for your installed kernel(s) (e.g. linux-lts-headers for linux-lts). [1] When either VirtualBox or the kernel is updated, the kernel modules will be automatically recompiled thanks to the DKMS Pacman hook.

Sign modules

When using a custom kernel with CONFIG_MODULE_SIG_FORCE option enabled, you must sign your modules with a key generated during kernel compilation.

Navigate to your kernel tree folder and execute the following command:

# for module in `ls /lib/modules/$(uname -r)/kernel/misc/{vboxdrv.ko,vboxnetadp.ko,vboxnetflt.ko,vboxpci.ko}` ; do ./scripts/sign-file sha1 certs/signing_key.pem certs/signing_key.x509 $module ; done
Note: Hashing algorithm does not have to match the one configured, but it must be built into the kernel.

Load the VirtualBox kernel modules

Since version 5.0.16, virtualbox-host-modules-arch and virtualbox-host-dkms use systemd-modules-load.service to load all four VirtualBox modules at boot time.

Note: If you do not want the VirtualBox modules to be loaded at boot time, you have to mask the default /usr/lib/modules-load.d/virtualbox-host-modules-arch.conf (or -dkms.conf) by creating an empty file (or symlink to /dev/null) with the same name in /etc/modules-load.d.

Among the kernel modules VirtualBox uses, there is a mandatory module named vboxdrv, which must be loaded before any virtual machines can run.

To load the module manually, run:

# modprobe vboxdrv

The following modules are optional but are recommended if you do not want to be bothered in some advanced configurations (precised here after): vboxnetadp, vboxnetflt and vboxpci.

  • vboxnetadp and vboxnetflt are both needed when you intend to use the bridged or host-only networking feature. More precisely, vboxnetadp is needed to create the host interface in the VirtualBox global preferences, and vboxnetflt is needed to launch a virtual machine using that network interface.
  • vboxpci is needed when your virtual machine needs to pass through a PCI device on your host.
Note: If the VirtualBox kernel modules were loaded in the kernel while you updated the modules, you need to reload them manually to use the new updated version. To do it, run vboxreload as root.

Finally, if you use the aforementioned "Host-only" or "bridge networking" feature, make sure net-tools is installed. VirtualBox actually uses ifconfig and route to assign the IP and route to the host interface configured with VBoxManage hostonlyif or via the GUI in Settings > Network > Host-only Networks > Edit host-only network (space) > Adapter.

Accessing host USB devices in guest

To use the USB ports of your host machine in your virtual machines, add users that will be authorized to use this feature to the vboxusers group.

Guest additions disc

It is also recommended to install the virtualbox-guest-iso package on the host running VirtualBox. This package will act as a disc image that can be used to install the guest additions onto guest systems other than Arch Linux. The .iso file will be located at /usr/lib/virtualbox/additions/VBoxGuestAdditions.iso, and may have to be mounted manually inside the virtual machine. Once mounted, you can run the guest additions installer inside the guest.

Extension pack

The Oracle Extension Pack which provides additional features, is released under a non-free license and only available for personal use. To install it, the virtualbox-ext-oracleAUR package is available, and a prebuilt version can be found in the seblu repository.

If you prefer to use the traditional and manual way: download the extension manually and install it via the GUI (File > Preferences > Extensions) or via VBoxManage extpack install <.vbox-extpack>, make sure you have a toolkit (like Polkit, gksu, etc.) to grant privileged access to VirtualBox. The installation of this extension requires root access.

Use the right front-end

Now, you are ready to use VirtualBox. Congratulations!

Multiple front-ends are available to you of which three are available by default:

  • If you want to use VirtualBox in command-line only (only launch and change settings of existing virtual machines), you can use the VBoxSDL command. VBoxSDL does only provide a simple window that contains only the pure virtual machine, without menus or other controls.
  • If you want to use VirtualBox in command-line without any GUI running (e.g. on a server) to create, launch and configure virtual machines, use the VBoxHeadless which produces no visible output on the host at all, but instead only delivers VRDP data (note: VRDP is only enabled if the extension pack is installed).
  • If you want to use VirtualBox with a GUI with menus usable via the mouse, you can run VirtualBox.

Finally, you can use PhpVirtualBox to administrate your virtual machines via a web interface.

Refer to the VirtualBox manual to learn how to create virtual machines.

Warning: If you intend to store virtual disk images on a Btrfs file system, before creating any images, you should consider disabling Copy-on-Write for the destination directory of these images.

Installation steps for Arch Linux guests

Boot the Arch installation media through one of the virtual machine's virtual drives. Then, complete the installation of a basic Arch system as explained in the Installation guide.

Installation in EFI mode

If you want to install Arch Linux in EFI mode inside VirtualBox, in the settings of the virtual machine, choose System item from the panel on the left and Motherboard tab from the right panel, and check the checkbox Enable EFI (special OSes only). After selecting the kernel from the Arch Linux installation media's menu, the media will hang for a minute or two and will continue to boot the kernel normally afterwards. Be patient.

Once the system and the boot loader are installed, VirtualBox will first attempt to run /EFI/BOOT/BOOTX64.EFI from the ESP. If that first option fails, VirtualBox will then try the EFI shell script startup.nsh from the root of the ESP. This means that in order to boot the system you have the following options:

  • Launch the bootloader manually from the EFI shell every time;
  • Move the bootloader to the default /EFI/BOOT/BOOTX64.EFI path;
  • Create a script named startup.nsh at the ESP root containing the path to the boot loader application, e.g. \EFI\grub\grubx64.efi.
  • Boot directly from the ESP partition using a startup.nsh script.

Do not bother with the VirtualBox Boot Manager (accessible with F2 at boot), as it is buggy and incomplete. It doesn't store efivars set interactively. Therefore, EFI entries added to it manually in the firmware (accessed with F12 at boot time) or with efibootmgr will persist after a reboot but are lost when the VM is shut down.

See also UEFI Virtualbox installation boot problems.

Install the Guest Additions

VirtualBox Guest Additions provides drivers and applications that optimize the guest operating system including improved image resolution and better control of the mouse. Within the installed guest system, install:

Both packages will make you choose a package to provide guest modules:

To compile the virtualbox modules provided by virtualbox-guest-dkms, it will also be necessary to install the appropriate headers package(s) for your installed kernel(s) (e.g. linux-lts-headers for linux-lts). [2] When either VirtualBox or the kernel is updated, the kernel modules will be automatically recompiled thanks to the DKMS Pacman hook.

  • You can alternatively install the Guest Additions with the ISO from the virtualbox-guest-iso package, provided you installed this on the host system. To do this, go to the device menu click Insert Guest Additions CD Image.
  • To recompile the vbox kernel modules, run rcvboxdrv as root.

The guest additions running on your guest, and the VirtualBox application running on your host must have matching versions, otherwise the guest additions (like shared clipboard) may stop working. If you upgrade your guest (e.g. pacman -Syu), make sure your VirtualBox application on this host is also the latest version. "Check for updates" in the VirtualBox GUI is sometimes not sufficient; check the virtualbox.org website.

Set optimal framebuffer resolution

Tango-go-next.pngThis article or section is a candidate for moving to VirtualBox/Tips and tricks.Tango-go-next.png

Notes: please use the second argument of the template to provide more detailed indications. (Discuss in Talk:VirtualBox#)

Typically after installing Guest Additions, a fullscreen Arch guest running X will be set to the optimal resolution for your display; however, the virtual console's framebuffer will be set to a standard, often smaller, resolution detected from VirtualBox's custom VESA driver.

To use the virtual consoles at optimal resolution, Arch needs to recognize that resolution as valid, which in turn requires VirtualBox to pass this information along to the guest OS.

First, check if your desired resolution is not already recognized by running the command:

hwinfo --framebuffer

If the optimal resolution does not show up, then you will need to run the VBoxManage tool on the host machine and add "extra resolutions" to your virtual machine (on a Windows host, go to the VirtualBox installation directory to find VBoxManage.exe). For example:

VBoxManage setextradata "Arch Linux" "CustomVideoMode1" "1360x768x24"

The parameters "Arch Linux" and "1360x768x24" in the example above should be replaced with your VM name and the desired framebuffer resolution. Incidentally, this command allows for defining up to 16 extra resolutions ("CustomVideoMode1" through "CustomVideoMode16").

Afterwards, restart the virtual machine and run hwinfo --framebuffer once more to verify that the new resolutions have been recognized by your guest system (which does not guarantee they will all work, depending on your hardware limitations).

Finally, add a video=resolution kernel parameter to set the framebuffer to the new resolution, for example video=1360x768.

Merge-arrows-2.pngThis article or section is a candidate for merging with GRUB/Tips_and_tricks#Setting_the_framebuffer_resolution.Merge-arrows-2.png

Notes: please use the second argument of the template to provide more detailed indications. (Discuss in Talk:VirtualBox#)

If you use GRUB as your bootloader, you can edit /etc/default/grub to include this kernel parameter in the GRUB_CMDLINE_LINUX_DEFAULT list, like so:

GRUB_CMDLINE_LINUX_DEFAULT="quiet video=1360x768"

The GRUB menu itself may also be easily set to optimal resolution, by editing the GRUB_GFXMODE option on the same configuration file:


On a standard Arch setup, you would then run grub-mkconfig -o /boot/grub/grub.cfg to commit these changes to the bootloader.

After these steps, the framebuffer resolution should be optimized for the GRUB menu and all virtual consoles.

Note: The GRUB settings GRUB_GFXPAYLOAD_LINUX and vga will not fix the framebuffer, since they are overriden by virtue of Kernel Mode Setting, which is mandatory for using X under VirtualBox and only allows for setting the framebuffer resolution by setting the kernel parameter described above.

Load the Virtualbox kernel modules

To load the modules automatically, enable vboxservice.service which loads the modules and synchronizes the guest's system time with the host.

To load the modules manually, type:

# modprobe -a vboxguest vboxsf vboxvideo

Since version 5.0.16, virtualbox-guest-modules-arch and virtualbox-guest-dkms use systemd-modules-load service to load their modules at boot time.

Note: If you do not want the VirtualBox modules to be loaded at boot time, you have to mask the default /usr/lib/modules-load.d/virtualbox-guest-modules-arch.conf (or -dkms.conf) by creating an empty file (or symlink to /dev/null) with the same name in /etc/modules-load.d.

Launch the VirtualBox guest services

After the rather big installation step dealing with VirtualBox kernel modules, now you need to start the guest services. The guest services are actually just a binary executable called VBoxClient which will interact with your X Window System. VBoxClient manages the following features:

  • shared clipboard and drag and drop between the host and the guest;
  • seamless window mode;
  • the guest display is automatically resized according to the size of the guest window;
  • checking the VirtualBox host version

All of these features can be enabled independently with their dedicated flags:

$ VBoxClient --clipboard --draganddrop --seamless --display --checkhostversion

As a shortcut, the VBoxClient-all bash script enables all of these features.

virtualbox-guest-utils installs /etc/xdg/autostart/vboxclient.desktop that launches VBoxClient-all on logon. If your desktop environment or window manager does not support this scheme, you will need to set up autostarting yourself, see Autostarting#Graphical for more details.

VirtualBox can also synchronize the time between the host and the guest, to do this, start/enable the vboxservice.service.

Now, you should have a working Arch Linux guest. Note that features like clipboard sharing are disabled by default in VirtualBox, and you will need to turn them on in the per-VM settings if you actually want to use them (e.g. Settings > General > Advanced > Shared Clipboard).

Hardware acceleration

Hardware acceleration can be activated from the VirtualBox options on the host computer. Note the GDM display manager 3.16+ is known to break hardware acceleration support. So if you get issues with hardware acceleration, try out another display manager (lightdm seems to work fine).[3] [4]

If you want to share folders between your host and your Arch Linux guest, read on.

Enable shared folders

Shared folders are managed on the host, in the settings of the Virtual Machine accessible via the GUI of VirtualBox, in the Shared Folders tab. There, Folder Path, the name of the mount point identified by Folder name, and options like Read-only, Auto-mount and Make permanent can be specified. These parameters can be defined with the VBoxManage command line utility. See there for more details.

No matter which method you will use to mount your folder, all methods require some steps first.

To avoid this issue /sbin/mount.vboxsf: mounting failed with the error: No such device, make sure the vboxsf kernel module is properly loaded. It should be, since we enabled all guest kernel modules previously.

Two additional steps are needed in order for the mount point to be accessible from users other than root:

Manual mounting

Use the following command to mount your folder in your Arch Linux guest:

# mount -t vboxsf shared_folder_name mount_point_on_guest_system

The vboxsf filesystem offers other options which can be displayed with this command:

# mount.vboxsf

For example if the user was not in the vboxsf group, we could have used this command to give access our mountpoint to him:

# mount -t vboxsf -o uid=1000,gid=1000 home /mnt/

Where uid and gid are values corresponding to the users we want to give access to. These values are obtained from the id command run against this user.


Note: Automounting requires the vboxservice to be enabled/started.

In order for the automounting feature to work you must have checked the auto-mount checkbox in the GUI or used the optional --automount argument with the command VBoxManage sharedfolder.

The shared folder should now appear in /media/sf_shared_folder_name. If users in media cannot access the shared folders, check that media has permissions 755 or has group ownership vboxsf if using permission 750. This is currently not the default if media is created by installing the virtualbox-guest-utils.

You can use symlinks if you want to have a more convenient access and avoid to browse in that directory, e.g.:

$ ln -s /media/sf_shared_folder_name ~/my_documents

Mount at boot

You can mount your directory with fstab. However, to prevent startup problems with systemd, comment=systemd.automount should be added to /etc/fstab. This way, the shared folders are mounted only when those mount points are accessed and not during startup. This can avoid some problems, especially if the guest additions are not loaded yet when systemd read fstab and mount the partitions.

sharedFolderName  /path/to/mntPtOnGuestMachine  vboxsf  uid=user,gid=group,rw,dmode=700,fmode=600,comment=systemd.automount  0  0
  • sharedFolderName: the value from the VirtualMachine's Settings > SharedFolders > Edit > FolderName menu. This value can be different from the name of the real folder name on the host machine. To see the VirtualMachine's Settings go to the host OS VirtualBox application, select the corresponding virtual machine and click on Settings.
  • /path/to/mntPtOnGuestMachine: if not existing, this directory should be created manually (for example by using mkdir)
  • dmode/fmode are directory/file permissions for directories/files inside /path/to/mntPtOnGuestMachine.}}

As of 2012-08-02, mount.vboxsf does not support the nofail option:

desktop  /media/desktop  vboxsf  uid=user,gid=group,rw,dmode=700,fmode=600,nofail  0  0

SSH from host to guest

The network tab of the virtual machine settings contains, in "Advanced", a tool to create port forwarding. It is possible to use it to forward the Guest ssh port 22 to a Host port, let's say 3022. Then :

user@host$ ssh -p 3022 $USER@localhost

will establish a connection from Host to Guest.

SSHFS as alternative to the shared folder

Using this port forwarding and sshfs, it is straightforward to mount the Guest filesystem onto the Host one :

user@host$ sshfs -p 3022 $USER@localhost:$HOME ~/shared_folder

and then transfer files between both.

Virtual disks management

See also VirtualBox/Tips and tricks#Import/export VirtualBox virtual machines from/to other hypervisors.

Formats supported by VirtualBox

VirtualBox supports the following virtual disk formats:

  • VDI: The Virtual Disk Image is the VirtualBox own open container used by default when you create a virtual machine with VirtualBox.
  • VMDK: The Virtual Machine Disk has been initially developed by VMware for their products. The specification was initially closed source, but it became now an open format which is fully supported by VirtualBox. This format offers the ability to be split into several 2GB files. This feature is specially useful if you want to store the virtual machine on machines which do not support very large files. Other formats, excluding the HDD format from Parallels, do not provide such an equivalent feature.
  • VHD: The Virtual Hard Disk is the format used by Microsoft in Windows Virtual PC and Hyper-V. If you intend to use any of these Microsoft products, you will have to choose this format.
Tip: Since Windows 7, this format can be mounted directly without any additional application.
  • VHDX (read only): This is the eXtended version of the Virtual Hard Disk format developed by Microsoft, which has been released on 2012-09-04 with Hyper-V 3.0 coming with Windows Server 2012. This new version of the disk format does offer enhanced performance (better block alignment), larger blocks size, and journal support which brings power failure resiliency. VirtualBox should support this format in read only.
  • Version 2 of the HDD: The HDD format is developed by Parallels Inc and used in their hypervisor solutions like Parallels Desktop for Mac. Newer versions of this format (i.e. 3 and 4) are not supported due to the lack of documentation for this proprietary format.
    Note: There is currently a controversy regarding the support of the version 2 of the format. While the official VirtualBox manual only reports the second version of the HDD file format as supported, Wikipedia's contributors are reporting the first version may work too. Help is welcome if you can perform some tests with the first version of the HDD format.
  • QED: The QEMU Enhanced Disk format is an old file format for QEMU, another free and open source hypervisor. This format was designed from 2010 in a way to provide a superior alternative to QCOW2 and others. This format features a fully asynchronous I/O path, strong data integrity, backing files, and sparse files. QED format is supported only for compatibility with virtual machines created with old versions of QEMU.
  • QCOW: The QEMU Copy On Write format is the current format for QEMU. The QCOW format does support zlib-based transparent compression and encryption (the latter has flaw and is not recommended). QCOW is available in two versions: QCOW and QCOW2. The latter tends to supersede the first one. QCOW is currently fully supported by VirtualBox. QCOW2 comes in two revisions: QCOW2 0.10 and QCOW2 1.1 (which is the default when you create a virtual disk with QEMU). VirtualBox does not support this QCOW2 format (both revisions have been tried).
  • OVF: The Open Virtualization Format is an open format which has been designed for interoperability and distributions of virtual machines between different hypervisors. VirtualBox supports all revisions of this format via the VBoxManage import/export feature but with known limitations.

Disk image format conversion


VirtualBox can handle back and forth conversion between VDI and VMDK by itself with VBoxManage clonehd.


$ VBoxManage clonehd source.vmdk destination.vdi --format VDI


$ VBoxManage clonehd source.vdi destination.vmdk --format VMDK

VHD to VDI and VDI to VHD

VirtualBox can handle conversion back and forth this format with VBoxManage clonehd too.


$ VBoxManage clonehd source.vhd destination.vdi --format VDI


$ VBoxManage clonehd source.vdi destination.vhd --format VHD

QCOW2 to VDI and VDI to QCOW2

VBoxManage clonehd cannot handle the QEMU format conversion; we will thus rely on another tool. The qemu-img command from qemu can be used to convert images back and forth from VDI to QCOW2.

Note: qemu-img can handle a bunch of other formats too. According to the qemu-img --help, here are the supported formats this tool supports: "vvfat vpc vmdk vhdx vdi ssh sheepdog sheepdog sheepdog raw host_cdrom host_floppy host_device file qed qcow2 qcow parallels nbd nbd nbd iscsi dmg tftp ftps ftp https http cow cloop bochs blkverify blkdebug'".


$ qemu-img convert -pO vdi source.qcow2 destination.vdi


$ qemu-img convert -pO qcow2 source.vdi destination.qcow2

As QCOW2 comes in two revisions (see #Formats supported by VirtualBox, use the flag -o compat= to specify the revision.

$ qemu-img convert -pO qcow2 source.vdi destination.qcow2 -o compat=0.10


$ qemu-img convert -pO qcow2 source.vdi destination.qcow2 -o compat=1.1
Tip: The -p parameter is used to get the progression of the conversion task.

Mount virtual disks


Mounting vdi images only works with fixed size images (a.k.a. static images); dynamic (dynamically size allocating) images are not easily mountable.

The offset of the partition (within the vdi) is needed, then add the value of offData to 32256 (e.g. 69632 + 32256 = 101888):

$ VBoxManage internalcommands dumphdinfo <storage.vdi> | grep "offData"

The can now be mounted with:

# mount -t ext4 -o rw,noatime,noexec,loop,offset=101888 <storage.vdi> /mntpoint/

You can also use mount.vdi script that, which you can use as (install script itself to /usr/bin/):

# mount -t vdi -o fstype=ext4,rw,noatime,noexec vdi_file_location /mnt/

Alternately you can use qemu's kernel module that can do this attrib:

# modprobe nbd max_part=16
# qemu-nbd -c /dev/nbd0 <storage.vdi>
# mount /dev/nbd0p1 /mnt/dir/
# # to unmount:
# umount /mnt/dir/
# qemu-nbd -d /dev/nbd0

If the partition nodes are not propagated try using partprobe /dev/nbd0; otherwise, a vdi partition can be mapped directly to a node by: qemu-nbd -P 1 -c /dev/nbd0 <storage.vdi>.

Compact virtual disks

Compacting virtual disks only works with .vdi files and basically consists in the following steps.

Boot your virtual machine and remove all bloat manually or by using cleaning tools like bleachbit which is available for Windows systems too.

Wiping free space with zeroes can be achieved with several tools:

  • If you were previously using Bleachbit, check the checkbox System > Free disk space in the GUI, or use bleachbit -c system.free_disk_space in CLI;
  • On UNIX-based systems, by using dd or preferably dcfldd (see here to learn the differences) :
# dcfldd if=/dev/zero of=/fillfile bs=4M
When fillfile reaches the limit of the partition, you will get a message like 1280 blocks (5120Mb) written.dcfldd:: No space left on device. This means that all of the user-space and non-reserved blocks of the partition will be filled with zeros. Using this command as root is important to make sure all free blocks have been overwritten. Indeed, by default, when using partitions with ext filesystem, a specified percentage of filesystem blocks is reserved for the super-user (see the -m argument in the mkfs.ext4 man pages or use tune2fs -l to see how much space is reserved for root applications).
When the aforementioned process has completed, you can remove the file fillfile you created.
  • On Windows, there are two tools available:
  • sdelete from the Sysinternals Suite, type sdelete -s -z c:, where you need to reexecute the command for each drive you have in your virtual machine;
  • or, if you love scripts, there is a PowerShell solution, but which still needs to be repeated for all drives.
PS> ./Write-ZeroesToFreeSpace.ps1 -Root c:\ -PercentFree 0
Note: This script must be run in a PowerShell environment with administrator privileges. By default, scripts cannot be run, ensure the execution policy is at least on RemoteSigned and not on Restricted. This can be checked with Get-ExecutionPolicy and the required policy can be set with Set-ExecutionPolicy RemoteSigned.

Once the free disk space have been wiped, shut down your virtual machine.

The next time you boot your virtual machine, it is recommended to do a filesystem check.

  • On UNIX-based systems, you can use fsck manually;
  • On Windows systems, you can use:
  • either chkdsk c: /F where c: needs to be replaced by each disk you need to scan and fix errors;
  • or FsckDskAll from here which is basically the same software as chkdsk, but without the need to repeat the command for all drives;

Now, remove the zeros from the vdi file with VBoxManage modifyhd:

$ VBoxManage modifyhd your_disk.vdi --compact
Note: If your virtual machine has snapshots, you need to apply the above command on each .vdi files you have.

Increase virtual disks

General procedure

If you are running out of space due to the small hard drive size you selected when you created your virtual machine, the solution adviced by the VirtualBox manual is to use VBoxManage modifyhd. However this command only works for VDI and VHD disks and only for the dynamically allocated variants. If you want to resize a fixed size virtual disk disk too, read on this trick which works either for a Windows or UNIX-like virtual machine.

First, create a new virtual disk next to the one you want to increase:

$ VBoxManage createhd -filename new.vdi --size 10000

where size is in MiB, in this example 10000MiB ~= 10GiB, and new.vdi is name of new hard drive to be created.

Next, the old virtual disk needs to be cloned to the new one which this may take some time:

$ VBoxManage clonehd old.vdi new.vdi --existing
Note: By default, this command uses the Standard (corresponding to dynamic allocated) file format variant and thus will not use the same file format variant as your source virtual disk. If your old.vdi has a fixed size and you want to keep this variant, add the parameter --variant Fixed.

Detach the old hard drive and attach new one, replace all mandatory italic arguments by your own:

$ VBoxManage storageattach VM_name --storagectl SATA --port 0 --medium none
$ VBoxManage storageattach VM_name --storagectl SATA --port 0 --medium new.vdi --type hdd

To get the storage controller name and the port number, you can use the command VBoxManage showvminfo VM_name. Among the output you will get such a result (what you are looking for is in italic):

Storage Controller Name (0):            IDE
Storage Controller Type (0):            PIIX4
Storage Controller Instance Number (0): 0
Storage Controller Max Port Count (0):  2
Storage Controller Port Count (0):      2
Storage Controller Bootable (0):        on
Storage Controller Name (1):            SATA
Storage Controller Type (1):            IntelAhci
Storage Controller Instance Number (1): 0
Storage Controller Max Port Count (1):  30
Storage Controller Port Count (1):      1
Storage Controller Bootable (1):        on
IDE (1, 0): Empty
SATA (0, 0): /home/wget/IT/Virtual_machines/GNU_Linux_distributions/ArchLinux_x64_EFI/Snapshots/{6bb17af7-e8a2-4bbf-baac-fbba05ebd704}.vdi (UUID: 6bb17af7-e8a2-4bbf-baac-fbba05ebd704)

Download GParted live image and mount it as a virtual CD/DVD disk file, boot your virtual machine, increase/move your partitions, umount GParted live and reboot.

Note: On GPT disks, increasing the size of the disk will result in the backup GPT header not being at the end of the device. GParted will ask to fix this, click on Fix both times. On MBR disks, you do not have such a problem as this partition table as no trailer at the end of the disk.

Finally, unregister the virtual disk from VirtualBox and remove the file:

$ VBoxManage closemedium disk old.vdi
$ rm old.vdi

Increase size for VDI disks

If your disk is a vdi one, simply run:

$ VBoxManage modifyhd your_virtual_disk.vdi --resize the_new_size

Then jump back to the Gparted step, to increase the size of the partition on the virtual disk.

Replace a virtual disk manually from the .vbox file

If you think that editing a simple XML file is more convenient than playing with the GUI or with VBoxManage and you want to replace (or add) a virtual disk to your virtual machine, in the .vbox configuration file corresponding to your virtual machine, simply replace the GUID, the file location and the format to your needs:

<HardDisk uuid="{670157e5-8bd4-4f7b-8b96-9ee412a712b5}" location="ArchLinux_vm.vdi" format="VDI" type="Normal"/>

then in the <AttachedDevice> sub-tag of <StorageController>, replace the GUID by the new one.

<AttachedDevice type="HardDisk" port="0" device="0">
  <Image uuid="{670157e5-8bd4-4f7b-8b96-9ee412a712b5}"/>
Note: If you do not know the GUID of the drive you want to add, you can use the VBoxManage showhdinfo file. If you previously used VBoxManage clonehd to copy/convert your virtual disk, this command should have outputted the GUID just after the copy/conversion completed. Using a random GUID does not work, as each UUID is stored inside each disk image.

Transfer between Linux host and other OS

The information about path to harddisks and the snapshots is stored between <HardDisks> .... </HardDisks> tags in the file with the .vbox extension. You can edit them manually or use this script where you will need change only the path or use defaults, assumed that .vbox is in the same directory with a virtual harddisk and the snapshots folder. It will print out new configuration to stdout.


 awk -v SetPath="$NewPath" -v SnapPath="$Snapshots" '{if(index($0,"<HardDisk uuid=") != 0){A=$3;split(A,B,"=");
 if(index($3,"{") != 0){SnapS=SnapPath}else{SnapS=""};
  print $1" "$2" location="\"SetPath SnapS L"\" "$4" "$5}
else print $0}' "$Filename"
  • If you will prepare virtual machine for use in Windows host then in the path name end you should use backslash \ instead of / .
  • The script detects snapshots by looking for { in the file name.
  • To make it run on a new host you will need to add it first to the register by clicking on Machine -> Add... or use hotkeys Ctrl+A and then browse to .vbox file that contains configuration or use command line VBoxManage registervm filename.vbox

Clone a virtual disk and assigning a new UUID to it

UUIDs are widely used by VirtualBox. Each virtual machines and each virtual disk of a virtual machine must have a different UUID. When you launch a virtual machine in VirtualBox, the latter will keep track of all UUID of your virtual machine instance. See the VBoxManage list to list the items registered with VirtualBox.

If you cloned a virtual disk manually by copying the virtual disk file, you will need to assign a new UUID to the cloned virtual drive if you want to use the disk in the same virtual machine or even in another (if that one has already been opened, and thus registered, with VirtualBox).

You can use this command to assign a new UUID to your virtual disk:

$ VBoxManage internalcommands sethduuid /path/to/disk.vdi
Tip: In the future, to avoid copying the virtual disk and assigning a new UUID to your file manually, use VBoxManage clonehd instead.
Note: The commands above supports all virtual disk formats supported by VirtualBox.

Tips and tricks

For advanced configuration, see VirtualBox/Tips and tricks.



To access the raw vmdk image on a windows host, run the VirtualBox GUI as administrator.

pacstrap script fails

If you used pacstrap in the #Installation steps for Arch Linux guests to also #Install the Guest Additions before performing a first boot into the new guest, you will need to umount -l /mnt/dev as root before using pacstrap again; a failure to do this will render it unusable.

Keyboard and mouse are blocked in my virtual machine

This means your virtual machine has captured the input of your keyboard and your mouse. Simply press the right Ctrl key and your input should control your host again.

To control transparently your virtual machine with your mouse going back and forth your host, without having to press any key, and thus have a seamless integration, install the guest additions inside the guest. Read from the #Install the Guest Additions step if you guest is Arch Linux, otherwise read the official VirtualBox help.

Cannot send CTRL+ALT+Fn key to my virtual machine

Your guest operating system is a GNU/Linux distribution and you want to open a new TTY shell by hitting Ctrl+Alt+F2 or exit your current X session with Ctrl+Alt+Backspace. If you type these keyboard shortcuts without any adaptation, the guest will not receive any input and the host (if it is a GNU/Linux distribution too) will intercept these shortcut keys. To send Ctrl+Alt+F2 to the guest for example, simply hit your Host Key (usually the right Ctrl key) and press F2 simultaneously.

Fix ISO images problems

While VirtualBox can mount ISO images without problem, there are some image formats which cannot reliably be converted to ISO. For instance, ccd2iso ignores .ccd and .sub files, which can give disk images with broken files.

In this case, you will either have to use CDemu for Linux inside VirtualBox or any other utility used to mount disk images.

VirtualBox GUI does not match my GTK Theme

See Uniform look for Qt and GTK applications for information about theming Qt based applications like Virtualbox.

OpenBSD unusable when virtualisation instructions unavailable

While OpenBSD is reported to work fine on other hypervisors without virtualisation instructions (VT-x AMD-V) enabled, an OpenBSD virtual machine running on VirtualBox without these instructions will be unusable, manifesting with a bunch of segmentation faults. Starting VirtualBox with the -norawr0 argument may solve the problem. You can do it like this:

$ VBoxSDL -norawr0 -vm name_of_OpenBSD_VM


This can occur if a VM is exited ungracefully. The solution to unlock the VM is trivial:

$ VBoxManage controlvm virtual_machine_name poweroff

USB subsystem is not working on the host or guest

Your user must be in the vboxusers group, and you need to install the extension pack if you want USB 2 support. Then you will be able to enable USB 2 in the VM settings and add one or several filters for the devices you want to access from the guest OS.

If VBoxManage list usbhost does not show any USB devices even if run as root, make sure that there is no old udev rules (from VirtualBox 4.x) in /etc/udev/rules.d/. VirtualBox 5.0 installs udev rules to /usr/lib/udev/rules.d/. You can use command like pacman -Qo /usr/lib/udev/rules.d/60-vboxdrv.rules to determine if the udev rule file is outdated.

Sometimes, on old Linux hosts, the USB subsystem is not auto-detected resulting in an error Could not load the Host USB Proxy service: VERR_NOT_FOUND or in a not visible USB drive on the host, even when the user is in the vboxusers group. This problem is due to the fact that VirtualBox switched from usbfs to sysfs in version 3.0.8. If the host does not understand this change, you can revert to the old behaviour by defining the following environment variable in any file that is sourced by your shell (e.g. your ~/.bashrc if you are using bash):


Then make sure, the environment has been made aware of this change (reconnect, source the file manually, launch a new shell instance or reboot).

Also make sure that your user is a member of the storage group.

Failed to create the host-only network interface

Make sure all required kernel modules are loaded. See #Load the VirtualBox kernel modules.

WinXP: Bit-depth cannot be greater than 16

If you are running at 16-bit color depth, then the icons may appear fuzzy/choppy. However, upon attempting to change the color depth to a higher level, the system may restrict you to a lower resolution or simply not enable you to change the depth at all. To fix this, run regedit in Windows and add the following key to the Windows XP VM's registry:

[HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows NT\Terminal Services]

Then update the color depth in the "desktop properties" window. If nothing happens, force the screen to redraw through some method (i.e. Host+f to redraw/enter full screen).

Use serial port in guest OS

Check you permission for the serial port:

$ /bin/ls -l /dev/ttyS*
crw-rw---- 1 root uucp 4, 64 Feb  3 09:12 /dev/ttyS0
crw-rw---- 1 root uucp 4, 65 Feb  3 09:12 /dev/ttyS1
crw-rw---- 1 root uucp 4, 66 Feb  3 09:12 /dev/ttyS2
crw-rw---- 1 root uucp 4, 67 Feb  3 09:12 /dev/ttyS3

Add your user to the uucp group.

Windows 8.x Error Code 0x000000C4

If you get this error code while booting, even if you choose OS Type Win 8, try to enable the CMPXCHG16B CPU instruction:

$ vboxmanage setextradata virtual_machine_name VBoxInternal/CPUM/CMPXCHG16B 1

Windows 8, 8.1 or 10 fails to install, boot or has error "ERR_DISK_FULL"

Update the VM's settings by going to Settings > Storage > Controller:SATA and check "Use Host I/O Cache".

Linux guests have slow/distorted audio

The AC97 audio driver within the Linux kernel occasionally guesses the wrong clock settings when running inside Virtual Box, leading to audio that is either too slow or too fast. To fix this, create a file in /etc/modprobe.d with the following line:

options snd-intel8x0 ac97_clock=48000

Guest freezes after starting Xorg

Faulty or missing drivers may cause the guest to freeze after starting Xorg, see for example [5] and [6]. Try disabling 3D acceleration in Settings > Display, and check if all Xorg drivers are installed.

"NS_ERROR_FAILURE" and missing menu items

If you encounter this message when first time starting the virtual machine:

Failed to open a session for the virtual machine debian.
Could not open the medium '/home/.../VirtualBox VMs/debian/debian.qcow'.
QCow: Reading the L1 table for image '/home/.../VirtualBox VMs/debian/debian.qcow' failed (VERR_EOF).
VD: error VERR_EOF opening image file '/home/.../VirtualBox VMs/debian/debian.qcow' (VERR_EOF).

Result Code: 
NS_ERROR_FAILURE (0x80004005)

Exit VirtualBox, delete all files of the new machine and from virtualbox config file remove the last line in MachineRegistry menu (or the offending machine you are creating):

  <MachineEntry uuid="{00000000-0000-0000-0000-000000000000}" src="/home/void/VirtualBox VMs/debian/debian.vbox"/>
  <MachineEntry uuid="{00000000-0000-0000-0000-000000000000}" src="/home/void/VirtualBox VMs/ubuntu/ubuntu.vbox"/>
  <MachineEntry uuid="{00000000-0000-0000-0000-000000000000}" src="/home/void/VirtualBox VMs/lastvmcausingproblems/lastvmcausingproblems.qcow"/>

This happens sometimes when selecting QCOW/QCOW2/QED disk format when creating a new virutal disk.

USB modem

If you have a USB modem which is being used by the guest OS, killing the guest OS can cause the modem to become unusable by the host system. Killing and restarting VBoxSVC should fix this problem.

"The specified path does not exist. Check the path and then try again." error in Windows guests

This error message often appears when running an .exe file which requires administrator priviliges from a shared folder in windows guests. See the bug report for details.

There are two workarounds:

  1. Disable UAC from Control Panel -> Action Center -> "Change User Account Control settings" from left side pane -> set slider to "Never notify" -> OK and reboot
  2. Copy the file from the shared folder to the guest and run from there

Other threads on the internet suggest to add VBOXSVR to the list of trusted sites, but this does not work with Windows 7 or newer.

No 64-bit OS client options

When launching a VM client, and no 64-bit options are available, make sure your CPU virtualization capabilities (usually named VT-x) are enabled in the BIOS.

If you are using a Windows host, you may need to disable Hyper-V, as it prevents VirtualBox from using VT-x. [7]

Host OS freezes on Virtual Machine start

Tango-view-fullscreen.pngThis article or section needs expansion.Tango-view-fullscreen.png

Reason: Needs a link to a bug report. (Discuss in Talk:VirtualBox#)

Possible causes/solutions :

  • SMAP

This is a known incompatiblity with SMAP enabled kernels affecting (mostly) Intel Broadwell chipsets. A solution to this problem is disabling SMAP support in your kernel by appending the nosmap option to your kernel parameters.

  • Hardware Virtualisation

Disabling hardware virtualisation (VT-x/AMD-V) may solve the problem.

  • Various Kernel bugs
    • Fuse mounted partitions (like ntfs) [8], [9]

Generally, such issues are observed after upgrading VirtualBox or linux kernel. Downgrading them to the previous versions of theirs might solve the problem.

Analog microphone not working in guest

If the audio input from an analog microphone is working correctly on the host, but no sound seems to get through to the guest, despite the microphone device apparently being detected normally, installing a sound server such as PulseAudio on the host might fix the problem.

If after installing PulseAudio microphone still refuses to work, setting 'Host Audio Driver'(Virtualbox->Machine->Settings->Audio->Host Audio Driver) to 'ALSA Audio Driver' might help.

Sound input (microphone) not working after upgrade

There has been issues reported around sound input in 5.1.x versions;


Downgrading may solve the problem.

You can use virtualbox-bin-5.0AUR to ease downgrading.

Fullscreen mode shows blank guest screen

On some window managers (i3, awesome), VirtualBox has issues with fullscreen mode properly due to the overlay bar. To workaround this issue, disable "Show in Full-screen/Seamless" option in "Guest Settings --> User Interface --> Mini ToolBar". See the upstream bug report for more information.

Failed to insert module

If you encounter problem when loading modules as follow:

Failed to insert 'vboxdrv': Required key not available

Make sure you signed your modules or disable CONFIG_MODULE_SIG_FORCE in your kernel config.

See also