VirtualBox Refusing to Launch Virtual Machines

VBAfter I upgraded to the latest version of VirtualBox, my virtual machines wouldn’t launch. The error reported did not seem very helpful — something like the following.

Failed to load VMMR0.r0 (VERR_SUPLIB_WORLD_WRITABLE).
Unknown error creating VM (VERR_SUPLIB_WORLD_WRITABLE)

Googling around, I found an entry in the VirtualBox.org forums from February 2011 that suggested removing world-writeable permissions from the OS X main Applications folder (/Applications). I checked, and sure enough, that folder on my system was world-writeable.

Wow! That’s troubling! That folder ought not be world-writeable! So, was the VirtualBox installer responsible for making it world-writeable? I don’t know, but making that change at the command line as follows resolved the problem.

    #sudo chmod o-w /Applications
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One thought on “VirtualBox Refusing to Launch Virtual Machines

  1. This problem occurred after upgrading to Lion. Other forums mention changing /usr permissions – I did that but no improvement. Also went through Disk Utility and repaired permissions. Also set the .vdi file to 755.

    I then changed /Applications and /Applications/VirtualBox.app to 755,

    sudo chmod 755 /Applications
    sudo chmod 755 /Applications/Virtualbox.app

    I have no idea why these files are set world writable!