My iMac crashes periodically (and more frequently lately) after going into sleep mode. It restarts as a blank screen with a mouse pointer, and it requires a restart. What is going on?
When leaving the iMac for a short while, it goes into sleep mode and moving or clicking the mouse or tapping the keyboard awakens it.
In the past (and lately more frequently) when you attempt to wake it the screen appears to light up (but remains blank) and only a moveable mouse pointer appears on the screen. The only solution is to restart the computer.
What is going on?
Thanks.
iMac, OS X Yosemite (10.10.3)