I removed the .Xauthority file in my directory (sudo rm .Xauthority in a terminal) and I was able to start Ubuntu 12.04 normally.
BUT, next time, same problem. I had to remove again this file to start Ubuntu next time.
It seems to be solved by an update of the Kernel today.
SOLVED !
I removed the .Xauthority file in my directory (sudo rm .Xauthority in a terminal) and I was able to start Ubuntu 12.04 normally.
BUT, next time, same problem. I had to remove again this file to start Ubuntu next time.
It seems to be solved by an update of the Kernel today.