Frequently Asked Questions for end users (User FAQ)

Here you can find common questions, frequently asked on the VirtualBox mailing lists and IRC channel, along with their answers. Please consult this list every time you run into a problem that is not described in the User Manual.

Note that we update the User Manual on a regular basis, and information that first shows up on this page is moved to the User Manual regularly. As a result, please do check the User Manual also, especially the "Troubleshooting" section.

Also make sure to check whether you are running the latest version of VirtualBox.

This particular FAQ is for end-user issues only; you may want to look at the Developer FAQ and Licensing FAQ for additional topics.

General

• Sometimes VirtualBox fails to start with a message on the lines of

  Failed to create VirtualBox COM object
   Callee RC: 0x80470007
  

  This usually means that the VirtualBox COM server was unable to start up, and is often a sign of problems in your installation of VirtualBox. In many cases this problem can be solved simply by reinstalling VirtualBox. Reinstalling will simply set up the VirtualBox program files again, and will not affect any virtual machines which you have created.

If this does not help, and you wish to investigate the problem further yourself, try starting the VirtualBox COM server (the program VBoxSVC in the VirtualBox program folder) from a command prompt or a DOS box. You may be able to see what is going wrong from error messages when the server starts.

Please do not open bug reports when you get this error before you have tried the other available support channels (​forums, mailing lists and IRC).

• "How come it doesn't detect my nVidia/ATI/whatever graphics card?"

Because the guest sees a virtual graphics card, not the host graphics card. The virtual graphics card provides the necessary VESA and VGA features to make the guest operative systems work OK. Additional features, like higher resolutions, is provided by the graphics driver included with the guest additions. More details on how to install guest additions and features of the virtual graphics card can be found in the manual.

Linux hosts

• Tickless Linux timer: VirtualBox currently does not work well on Linux kernels with tickless timer support (CONFIG_NO_HZ enabled). We are investigating the problem but in the meantime you should disable the tickless timer by disabling that config option or by adding nohz=off to the Linux kernel command line.

• If you get a message saying "VirtualBox kernel driver not accessible, permission problem" when starting VirtualBox immediately after installation, make sure that your user account is a member of the vboxusers group. This group is created when VirtualBox is installed, but you will need to manually add all users to it who are to be allowed to run VirtualBox. The documentation accompanying your Linux distribution should provide information about how to do this. If not, the following should also work on most Linux systems. These commands should be run as the Administrator user from the command line.

  # groups <login name>
  [Shows a list of groups for that login name]
  # useradd <login name> -g <first group in list> -G <second group>,<third group>,...,vboxusers
  

  These changes will only take effect after the users have logged out and back in again.

• If the kernel module refuses to load with a message saying "Error inserting vboxdrv: Invalid argument", check (as root) the output of the "dmesg" command, and see "Troubleshooting" -> "Linux hosts" in the User Manual for solutions.

• If USB doesn't work, check your usbfs permissions. See "Troubleshooting" -> "Linux hosts" in the User Manual for a solution.

Windows hosts

• Windows Vista hosts might show an error about a COM server not being accessible. This is a problem of our installation routine which we have not figured out yet. To fix the problem, open a command prompt shell and enter:

  cd \Programs\InnoTek VirtualBox
  VBoxSVC.exe /ReRegServer
  regsvr32.exe VBoxC.dll
  

Windows Vista guests

• There is no networking in Windows Vista guests initially because, unfortunately, with Vista, Microsoft dropped driver support for the virtual AMD PCnet card that we are providing. See "Troubleshooting" -> "Windows guests" in the User Manual for a solution. The VirtualBox Guest Additions contain the AMD PCnet driver.

High CPU load while running Windows 98

• That is a problem of Win98. This guest is not executing the 'hlt' instruction when idle. Download and install rain20 from

​http://www.benchtest.com/downloads/index.html.

Linux guests