Hi all - Something unusual happened on my iMac last night and this morning - The screen briefly blurred out or turned fuzzy. almost like it was vibrating. The mouse would freeze on the screen when it happened and it only would last for a second or two...except for one time where it went for 4 or 5 seconds. This happened last night 2-3 times in a short time span, and I repaired permissions, restarted it and went to bed. This morning it happened again once when I was checking my email, but this time just in the Mail app window (vs. the whole screen last night). I had to leave for work so I just shut it down completely and left it turned off. I've never seen this happen before - Does anyone know what is causing this and/or what I can do to prevent it from happening in the future? Thanks in advance!