I have detect the source of the problem!
Xorg crashes only when machine go to S3 sleep with active Virtualbox on fullscreen! And when virtualbox is in window, it sleeps and resume normally.
I have created a bug report at virtualbox bugtracker: http://www.virtualbox.org/ticket/4169
I have detect the source of the problem! www.virtualbox. org/ticket/ 4169
Xorg crashes only when machine go to S3 sleep with active Virtualbox on fullscreen! And when virtualbox is in window, it sleeps and resume normally.
I have created a bug report at virtualbox bugtracker: http://