iMac system issues
I too seem to be having what seems a similar problem. Was working on my iMac (OS 10.10.4) yesterday when in the middle of doing nothing other than typing, the system seemed to go into a convulsion of sorts with a repeating staccato sound, flashing screen and the only way it would stop was to push the power button to restart. This had happened 2 or 3 times over the previous week as well, which rebooted the system without problem. This time however, the system will reboot only to the white startup screen, the status bar getting to about 25% and going no farther before the white screen is joined momentarily by a 1/4" horizontal band of pixelated color across the top, before the screen goes to black, then reboots itself, only to repeat the process all over again.
I have reset the PRAM per suggestion as well unplugged the iMac overnight, have tried a "SafeStart", but nothing seems to make a difference as I cannot get passed the above description. I do run antivirus software and have not been prompted of any problems. Of course, I was "just going to run a full backup" so that has not been done for a few months. I sadly I disconnect my external HD and TimeMachine back up when I moved some things around and forgot to reconnect it all .... duh!
Everything "sounds and looks" fine, until it won't proceed any further. Any thoughts or assistance would be GREATLY appreciated.
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