I'm having the exact same problem on my 1st generation Mac Mini.
Ok here's an odd one. Using my Core2 iMac with no issues after updated to 10.6.5 (Combo Update). Last nite, I logout only to see the Logon Window come up no longer showing any users .. just "Other"? I don't even have "Other" enabled in my Login Preferences?
Making matters worse, no username/password I specify is accepted meaning I cannot logon to the machine. So I do the following:
- Boot to an external startup drive
- run Disk Utility
- the Internal HD does NOT appear on the desktop but does appear in Disk Utility
- Run Repair Disk and Repair Permissions which both make repairs.
Reboot to Internal HD. Still only the "Other" user appears. I haven't had time to do it yet but was going to try booting in Target Disk mode to see if I can access the internal HD.
If not I guess I can just do a clean install and recover from my Time Machine backups. Anyone else seeing this issue? Any other ideas?