I just upgraded recently to 10.9.1 from 10.8.5. I don't know if this has anything to do with my problem, but holding down the option key when restarting doesn't work at all. I get about 30 seconds of a grey screen, then a cursor appears, and nothing happens. I can wait forever and the drives that contain boot volumes do not show up. The only way I can boot off a different drive is to select the new location in System Prefs. This works when everything is fine, but I'm concerned that if anything happens to my boot drive, I'm hosed because I can't seem to get holding down the option key to work. Any suggestions?