Hello! Hopefully I can shed some light on this issue, because it just happened to an Intel Mac at work.
I'm doing this with hopes that someone may find out what happened, because I really would like to know.
2.16 Ghz Intel Core 2 Duo
2 GB 667 MHz DDR2 (replaced original RAM with Corsair, 2GB, months ago)
Mac OS X 10.4.9
The Mac experienced most of the same symptoms as everyone else:
The computer had been on and being used all day with nothing unusual happening.
It was near the end of the day that the employee noticed Photoshop brushes, effects and very likely many other things completely disappear from the system. (who know what elso had also disappeared.)
The employee shut down the computer and went home.
The next morning, after turning on the computer, it went to a desktop identical to a freshly installed system user's profile.
All applications were still installed, however they did not need to be registered again (because the operating system version never changed, which apparently reacted like a Windows XP repair install and required registration). Nevertheless, in applications (Photoshop) it showed welcome settings and windows it only shows the first time after installing it.
Other user-created folders in the root directory of the hard drive were still there. The operating system version never changed.
After running Disk Utility from the OS X CD, I tried booting into safe mode (holding down shift at startup), and it gave me the following error:
http://img516.imageshack.us/my.php?image=safebooterrorxg2.jpg
That error makes it look like the bios became faulty or something...
Next I went back into OS X and looked at the user accounts, because that is obviously the main thing that got mixed up.
Prior to this incident, there was only one user: meeker.
Now, there is still only one user, however the name is: Admin, whose short name is: meeker.
Here's the GREAT news: I was snooping around the hard drive and just noticed a folder in the root directory of the drive called: Previous Systems.
Inside that were the following folders:
- meeker (which contained the missing user profile folders/data)
- Previous Systems 1 (which contained: Applications, Library, private, System, Users and a file called mach.sym - yes there were applications in the apps folder, tons of stuff in the library folder, etc)
I do not know if that Previous Systems folder was there the first time after booting up.
Thank God!! Because on the employee's desktop was THOUSANDS of dollars worth of data that hadn't been backed up yet. (yes, I scolded the employee)
Another symptom being experienced long BEFORE any of this that might be noteworthy:
Frequently when turning on the computer in the morning, instead of showing the Apple logo and loading logo it shows a Globe and just sits there. Unplugging the network cable and restarting always fixes the problem.
Hope this helps figure out the problem, because at this point I don't feel safe having the employee going back to work on that computer.
DiFFeReNT