VirtualBox on OSX Host: Signal 6 Error, can only run headless


I am unable to start any of my VMs interactively. They work when run headless however (--type vrdp)

If I try to run normally I get:

$ VBoxManage startvm Kubuntu
Waiting for the VM to power on...
VBoxManage: error: The virtual machine 'Kubuntu' has terminated unexpectedly during startup because of signal 6
VBoxManage: error: Details: code NS_ERROR_FAILURE (0x80004005), component Machine, interface IMachine, callee 

My host machine is an Intel iMac running 10.6.7, and I'm using VirtualBox 4.0.6 with the Oracle extensions installed.

Any ideas?

Further info: The virtual machines start up just fine interactively if I use sudo. That seems to imply there is some sort of bad permission or locked file or something somewhere, but I have already checked all the files in Library/VirtualBox.

asked on Super User May 7, 2011 by Eggplant Jeff • edited May 7, 2011 by Toby Allen

2 Answers


I had this exact problem with all my VMs running on Mac OS X 10.7.5 host. A reboot solved the problem, since none of the .vbox files seemed to have any problems.

answered on Super User Nov 25, 2012 by Kekoa

Firstly, backup your VM (including the disk image and everything that goes with it).

Then, go into the folder in which your VM is held. In there, you should see a file called "VirtualBox.xml", and HOPEFULLY, a file called "VirtualBox.xml-prev". Rename the "VirtualBox.xml" file to "VirtualBox.xml.old", and then rename "VirtualBox.xml-prev" to "VirtualBox.xml". Try starting your VM again - the error should be gone.

If you don;'t have a VirtualBox.xml-prev file, then try creating a new VM, and use your old disk image. That process will re-create the VirtualBox.xml file for you.

Remember to back up!

answered on Super User May 7, 2011 by Joseph Redfern

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