Some Oracle VM VirtualBox features are labeled as experimental. Such features are provided on an "as-is" basis and are not formally supported. However, feedback and suggestions about such features are welcome. A comprehensive list of experimental features is as follows:
Hardware 3D acceleration support for Windows, Linux, and Oracle Solaris guests
Hardware 2D video playback acceleration support for Windows guests
PCI pass-through (Linux hosts only)
Mac OS X guests (Mac OS X hosts only)
ICH9 chipset emulation
Host CD/DVD drive pass-through
Support of iSCSI using internal networking
Using Oracle VM VirtualBox and Hyper-V on the same host
The following section describes known problems with this release of Oracle VM VirtualBox. Unless marked otherwise, these issues are planned to be fixed in later releases.
The following Guest SMP (multiprocessor) limitations exist:
Poor performance with 32-bit guests on AMD CPUs. This affects mainly Windows and Oracle Solaris guests, but possibly also some Linux kernel revisions. Partially solved in 3.0.6 for 32-bit Windows NT, 2000, XP, and 2003 guests. Requires Guest Additions 3.0.6 or later to be installed.
Poor performance with 32-bit guests on certain Intel CPU models that do not include virtual APIC hardware optimization support. This affects mainly Windows and Oracle Solaris guests, but possibly also some Linux kernel revisions. Partially solved in 3.0.12 for 32-bit Windows NT, 2000, XP, and 2003 guests. Requires Guest Additions 3.0.12 or later to be installed.
NX (no execute, data execution prevention) only works for guests running on 64-bit hosts or guests running on 32-bit hosts with PAE enabled and requires that hardware virtualization be enabled.
For basic Direct3D support in Windows guests to work, the Guest Additions must be installed in Windows safe mode. Press F8 when the Windows guest is booting and select Safe Mode, then install the Guest Additions. Otherwise the Windows file protection mechanism will interfere with the replacement DLLs installed by Oracle VM VirtualBox and keep restoring the original Windows system DLLs.
This does not apply to the WDDM Direct3D video driver available for Vista and Windows 7 guests shipped with Oracle VM VirtualBox 4.1.
Guest control. On Windows guests, a process started using the guest control execute support will not be able to display a graphical user interface unless the user account under which it is running is currently logged in and has a desktop session.
Also, to use accounts without or with an empty password, the
guest's group policy must be changed. To do so, open the group
policy editor on the command line by typing
gpedit.msc, open the key
Settings\Security Settings\Local Policies\Security
Options and change the value of
Accounts: Limit local account use of blank
passwords to console logon only to Disabled.
Compacting virtual disk images is limited to VDI files. The VBoxManage modifyhd --compact command is currently only implemented for VDI files. At the moment the only way to optimize the size of a virtual disk images in other formats, such as VMDK or VHD, is to clone the image and then use the cloned image in the VM configuration.
OVF localization, with multiple languages in a single OVF file, is not yet supported.
Some OVF sections like StartupSection, DeploymentOptionSection, and InstallSection are ignored.
OVF environment documents, including their property sections and appliance configuration with ISO images, are not yet supported.
Remote files using HTTP or other mechanisms are not yet supported.
Neither scale mode nor seamless mode work correctly with guests using OpenGL 3D features, such as with compiz-enabled window managers.
The RDP server in the Oracle VM VirtualBox extension pack supports only audio streams in format 22.05kHz stereo 16 bit. If the RDP client requests any other audio format there will be no audio.
Preserving the aspect ratio in scale mode works only on Windows hosts and on Mac OS X hosts.
On Mac OS X hosts, the following features are not yet implemented:
CPU frequency metric
Mac OS X guests:
Mac OS X guests can only run on a certain host hardware. For details about license and host hardware limitations. See Section 3.1.1, “Mac OS X Guests” and check the Apple software license conditions.
Oracle VM VirtualBox does not provide Guest Additions for Mac OS X at this time.
The graphics resolution currently defaults to 1024x768 as Mac OS X falls back to the built-in EFI display support. See Section 3.14.1, “Video Modes in EFI” for more information on how to change EFI video modes.
Mac OS X guests only work with one CPU assigned to the VM. Support for SMP will be provided in a future release.
Depending on your system and version of Mac OS X, you might experience guest hangs after some time. This can be fixed by turning off energy saving. Set timeout to "Never" in the system preferences.
By default, the Oracle VM VirtualBox EFI enables debug output of the Mac OS X kernel to help you diagnose boot problems. Note that there is a lot of output and not all errors are fatal. They would also show when using a physical Apple Macintosh computer. You can turn off these messages by using the following command:
VBoxManage setextradata "VM name" "VBoxInternal2/EfiBootArgs" " "
To revert to the previous behavior, use the following command:
VBoxManage setextradata "VM name" "VBoxInternal2/EfiBootArgs" ""
It is currently not possible to start a Mac OS X guest in safe mode by specifying "-x" option in "VBoxInternal2/EfiBootArgs" extradata.
Oracle Solaris hosts:
There is no support for USB devices connected to Oracle Solaris 10 hosts.
USB support on Oracle Solaris hosts requires Oracle Solaris 11 version snv_124 or later. Webcams and other isochronous devices are known to have poor performance.
Host Webcam passthrough is restricted to 640x480 frames at 20 frames per second due to limitations in the Oracle Solaris V4L2 API. This may be addressed in a future Oracle Solaris release.
No ACPI information, such as battery status or power source, is reported to the guest.
No support for using wireless adapters with bridged networking.
Crossbow-based bridged networking on Oracle Solaris 11
hosts does not work directly with aggregate links.
However, you can use
dladm to manually create
a VNIC over the aggregate link and use that with a VM.
This limitation does not exist in Oracle Solaris 11u1
build 17 and newer.
Guest Additions of version 4.1, 4.1.2 and 4.1.4 for Windows. The Oracle VM VirtualBox WDDM Video driver may be installed and remain in the guest system when Guest additions uninstallation is performed. This is caused by a bug in Guest Additions uninstaller.
This does not apply to a Guest Additions update. Installing one version of Guest Additions on top of another works correctly.
To solve this problem, uninstall the Oracle VM VirtualBox WDDM Video driver manually. Open Device Manager, and check whether the Display Adapter is named "Oracle VM VirtualBox Graphics Adapter ..". If not, there is nothing to be done. If it is, right-click the Oracle VM VirtualBox Graphics Adapter in Device Manager, select Uninstall, check Delete the Driver Software for this Device and click OK. Once uninstallation is done, start Device Manager, go to the Action menu and select Scan for Hardware Changes to ensure that the correct Windows default driver be picked up for the Graphics adapter.
Neither virtio nor Intel PRO/1000 drivers for Windows XP guests support segmentation offloading. Therefore Windows XP guests have slower transmission rates comparing to other guest types. Refer to MS Knowledge base article 842264 for additional information.
Guest Additions for OS/2. Seamless windows and automatic guest resizing will probably never be implemented due to inherent limitations of the OS/2 graphics system.
Some guest operating systems predating ATAPI CD-ROMs may exhibit long delays or entirely fail to boot in certain configurations. This is most likely to happen when an IDE/ATAPI CD-ROM exists alone on a primary or secondary IDE channel.
Affected operating systems are MS OS/2 1.21: fails to boot with an error message referencing COUNTRY.SYS and MS OS/2 1.3: long boot delays. To avoid such problems, disable the emulated IDE/ATAPI CD-ROM. The guest OS cannot use this device, anyway.