VirtualBox wont start in first user session

[gilado]

I start the machine, login, start VirtualBox and get

Invalid MIT-MAGIC-COOKIE-1 keyFailed to open the X11 display!

I then click the PC button, select leave, Switch User, New User, and get a second user session.

I login as a second user (same username), start VirtualBox and it work.

When I switch between the two sessions, the first one (that does not work) is ctrl-alt-F7 and the second one (that does work) is ctrl-alt-F8.

This is a new problem that started after an update a few weeks ago.

[GermanTux]

OK - first what version of Virtualbox are you using?

Second, go to your virtual machine->settings-display.  Make sure you have at least 24mb of video memory, and uncheck both 3d and 2d acceleration.  Give that a try.