10 Replies Latest reply: Nov 25, 2012 11:17 AM by BDAqua
nowsthetime Level 1 Level 1 (0 points)

Every now and then my iMac forgets which is my startup disk.

I have two external drives attached.

I HAVE made the selection in system preferences many times, but occasionally, when I start up, instead of the apple, I get a blank screen.  If I unplug the attached drives, the computer starts up properly.  Then I plug the drives back in.

One of the external drives is bootable, but even when I leave that one turned off, the other drive which is NOT bootable but which is used as time machine backup (and doesn't have an on-off switch, so must be unplugged), seems to cause the same problem.

And yes, I've repaired permissions regularly...