Blank Screen Using Fast User Switching In Tiger


Soon after receiving my new iMacG5 with Tiger preinstalled, I noticed that occasionally the computer would
"blank out" when I attempted a fast-user switch between accounts. The swiveling cube would swivel, but it would swivel to a blank screen with only the mouse pointer on it. I couldn't think of anything short of a forced power-down of the system to get out of his situation. Later, I upgraded to 10.4.2 and thought that this would solve the problem. However, the same thing happened yesterday. The computer had been running two-three open accounts for four days, but I can't imagine that would cause it. I am aware this occasionally happened in Panther if all accounts did not have Fast User switching on, but I think the control is universal in Tiger, plus this is an infrequent bug that I cannot seem to force. Any ideas?