here is ubuntu 12.10

virtual-box is somehow not working:

I was trying to install win7 on to an usb-hard-disk.

boinc is switched off and RAM-size is set to 4096 MB (too big ? of possible 8 Gibi )

report of virtual-box is:

the com-object for virtualbox could not be created.

the application is now ended.

Start tag expected, '<' not found.

Location: '/home/$user/.VirtualBox/VirtualBox.xml', line 1 (0), column 1.

/build/buildd/virtualbox-4.1.18-dfsg/src/VBox/Main/src-server/VirtualBoxImpl.cpp[484] (nsresult VirtualBox::init()).

Fehlercode:NS_ERROR_FAILURE (0x80004005)
Interface:IVirtualBox {c28be65f-1a8f-43b4-81f1-eb60cb516e66}

comment of me: why is virtualbox installing xml into folder of $user in .VirtualBox ? should it not be on usb-harddisk ? (with 500 Gibi )

first installation attempt was breaking off (with win7 in 64Bit) should I try virtual-box (ubuntu 64Bit) with win7 in 32Bit ? should I leave RAM-size of virtual-box to default 512 MB ?

thanks for reply

  • Just so you guys know. NS_ERROR_FAILURE occured when I didn't shut down windows properly. I ran ntfsfix /dev/sda1 (change sda to your drive and 1 to you partition number) in the drive which had the virtualbox files (it was in a seperate ntfs drive). And I mounted it, and it worked. – Example person Jul 19 '20 at 13:04

14 Answers 14


There seems to be nothing wrong with your Virtual Box settings. However the error you see may be related to a previous fail to install Windows leaving unwanted reference to this installation in your Virtual Box settings (that are usually and correctly located in your $HOME).

The issue also may also have come from an installation to a removable drive. Installing the virtual disk .vdi file to an external USB drive is possible but it may lead to unwanted side effects from changed media location or mount points. In addition we then need to make sure the virtualbox user has read and write access to this external drive. Also we obviously should then not access this USB drive from the virtual OS.

To solve the issue you may find a solution in the following question where people recommend reinstalling Virtual Box:

  • Make sens. I have 5 internal drives on my 18.04. One smaller ssd for startup and 4 remaining big ones for everything else. However. None of the .vdi's pointing to the 1st drive where the OS and VBox installation are set up. My setup is that every time my machine is rebooted all remaining 4 drives are enabled on the startup, but not mounted, until I physically start browsing them and mount it. In effect if I run my VBox instance before mounting the drive where my vdi's are pointing, I'll get this funny NS_ERROR_FAILURE (0x80004005) – Adam Filipczyk May 18 '20 at 20:03

The most simple decision, that i found:

  1. enter into the folder /home/$user/.VirtualBox/
  2. find there file VirtualBox.xml-prev, this is backed up the configurations of Virtual Box
  3. delete VirtualBox.xml
  4. and change name VirtualBox.xml-prev to VirtualBox.xml.
  • Had the same issue on OSX, solution was the same except that I had to reboot my machine before doing those 4 steps. – Jones03 Aug 8 '17 at 2:55
  • 3
    Thanks, now all my machines are gone and the problem still exists :( – Jakke Jan 30 '18 at 17:12
  • 1
    Im my case VirtualBox.xml was located here ~/.config/VirtualBox/VirtualBox.xml. – holzkohlengrill Oct 27 '20 at 9:51
  • Thanks! This worked for me. – Konrad Gajewski Oct 28 '20 at 3:48
  • for me, on macOS Mojave, VirtualBox.xml was located at ~/Library/VirtualBox – Derwent Nov 29 '20 at 4:13

Probably due to some updates. It happened to me. A simple command can fix the problem:

sudo /etc/init.d/vboxdrv setup
  • Thanks @hdoghmen ! It worked. It happened to me when I upgraded my ubuntu 14.04 to 16.04. – Visvendra Singh Rajpoot Mar 27 '17 at 3:11

I had installed VirtualBox from universal repository, and I solved with this command:

sudo dpkg-reconfigure virtualbox-dkms

The file /home/$user/.VirtualBox/VirtualBox.xml is not valid. It's not valid XML. More then likely you edited the file by hand or some other tool did.

Your ram sizes and everything else seem fine.

Can you pastie the config file, maybe it's something easy we can fix.

  • sorry, for my inconvenience. hmmm, also from beginning new ... I need a formatted hard-disk (usb) with ntfs ? or an empty usb-disk with nothing ? does this ntfs-partition need a partition-table for virtualbox resp. for win7 ? (now virtualbox 4.2.4 is installed with extension-pack for usb - extension pack was missing before) – dschinn1001 Nov 16 '12 at 11:22
  • forgot to add $user as member for group vboxusers. means then I need 2 entries: 1 $user for usb - harddisk and 1 $user for vboxusers ? – dschinn1001 Nov 16 '12 at 11:36
  • yeah, now it is solved. and there was "driver-trouble" on different server of Microsoft. the older virtualbox was nagging about full usb-harddisk (it was meant the main harddisk on the system - and I thought usb-harddisk has to be unformatted, but that was wrong). so the actual virtualbox was not nagging and usb-harddisk was formatted with partition-table (for usb-harddisk). - now everything works and this main question is solved. – dschinn1001 Nov 16 '12 at 13:20

If you're using Oracle Virtualbox you can try recompiling everything by running /sbin/vboxconfig as root which executes vboxdrv.sh. This works with Ubuntu 16.04 and Virtualbox 5.1


I had such an error because ~/.config/VirtualBox/VirtualBox.xml was empty. Just deleting it made it work for me.

  • I'd recommend backing it up before you delete it, though, just in case it isn't empty! – tu-Reinstate Monica-dor duh Feb 26 '18 at 6:08
  • If it isn't empty, I don't advise deleting it! If something about it is corrupt, try to repair it. – nafg Feb 27 '18 at 12:36

I got this problem and my VirtualBox was installed from VirtualBox.org. I installed(didn't bother to uninstall) VirtualBox again using

sudo apt-get install virtualbox

And this started working fine, yeah!!!


My perspective in general for all errors, missing files/packages,etc; is:

  1. Restart into the most updated generic linux headers (recovery mode)

  2. Do the following in order:

    check file system checker
    repair broken packages
    clean system
  3. Resume boot

  4. restart again as in the standard grub boot loader

  5. Start virtual box again and solved.

I feel this goes for most problems and bypasses researching and entering codes when it does everything for you (finding missing files and repairs them, repairs pakcges, and cleans out the unneccesary)

  • 1
    check file system, repair broken packages, clean system, resume boot, then restart again, then start virutal box again – Wes Jun 14 '18 at 17:33

This issue happened to me after the process of setting up a virtual machine failed.
It was resolved after deleting (or renaming) the /home/{user}/.config/Virtualbox folder


Solutions varies from people.
Some problems of hardware occured that the disk where I installed my virtual machines became read-only
I booted that disk (windows 10) and reboot back, trying to remove the problems.
It worked.
I found that when I attempted to apply changes of my virtual machine.


Had this same problem on a Mac OS I removed the VirtualBox.xml and it then

rm VirtualBox.xml
dpkg-reconfigure virtualbox-dkms
service virtualbox restart

Run the following commands in terminal:

ls -la .VirtualBox/VirtualBox.xml*
cp .VirtualBox/VirtualBox.xml-prev .VirtualBox/VirtualBox.xml
  • 6
    Could you perhaps add more detail to your answer? Explaining what this does and why? Thanks. – Seth Jan 8 '13 at 16:37

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