A gray screen appears at start up with the apple icon, and an "update" bar. The update seems to happen but then just after completion the computers powers down. What do I do?
A gray screen appears at start up with the apple icon, and an "update" bar. The update seems to happen but then just after completion the computers powers down. What do I do?
iMac (21.5-inch Mid 2011), OS X Mountain Lion (10.8.2)