I am running Mountain Lion on a late-2012 Mac Mini (the newest one at this writing), and my system got messed up after I tried to reset my primary uid to 501 (I know, first mistake) after having migrated the system from an older Mac Mini. This worked partially, but I continued to have issues accessing some files and got tired of resetting the permissions manually.
I tried reinstalling Mountain Lion and since then, the system fails to boot completely. I can get as far as seeing the desktop, Finder menu, Dock, etc., but then one or more error windows pop up relating to specific resources (I think Calendar Agent was one of them, I can't remember because I then saw the spinning disk icon and the system stopped responding). I tried restarting by turning the computer off and then on again, but continue to get similar errors after it gets almost all the way through booting.
Although I have much of my data on the hard drive backed up to an external Seagate drive on my home network, I had not been able to do a complete backup because I have many old (pre-OS X) files that contain slashes or other characters no longer allowed in filenames, and it has proven too cumbersome to update all the filenames to make it worthwhile. Thus, I am not able to wipe the hard drive and start from scratch.
I know how to boot in Single-User mode, which does work, but don't know enough BSD/Darwin to pinpoint the source of this problem and fix it.
Any advice about how to diagnose and/or solve this problem? I would like to be able to correct any uid and gid conflicts that may be causing this, which I believe would work, but am not sure how to do this. I am writing this from Safari after booting in Recovery mode.
Thanks for any help with this. - Klingon725