I recently installed 11.3 x64. Since then the desktop will freeze at random times. This freeze will last for a few minutes to a few hours. I can use any opened program normally, I can open new programs with the quick run (alt+f2) although this will hang sometimes when pre-loading the program icon and name. I can access the programs in the task bar: pidgin, amarok, klipper, will all maximize from the tray fine. I have since updated the nvidia drivers, and tried different desktop themes in case it was the cause, it unfortunatly was not the issue. Desktop effects work normally during the freeze, disabling and enabling do not make a difference. When the desktop does unfreeze, everything on the desktop that I clicked while it was frozen will activate. I only have the kde desktop installed.