It's hard for me to say definitively, as I've only worked on one or two computers with such a problem; probably mostly just things like inability to boot or log in. In general, just something that can't be fixed by either an archive and install preserving users or a new user. Like any software corruption, there are practically infinite causes; a crash at an inopportune time, a corrupted directory resulting in overlapped files, bad RAM, a bad processor, a rare bug perhaps... Just to name a few. The only real way to fix it is an archive and install *not* preserving users and network settings (which can also get messed up sometimes). As long as your user folder is OK though, you can just copy back the entire contents of your user folder into the new user you create in the Setup Assistant, log out and back in, and everything will be just the same as before the reinstall, minus any system-level additions you might have (like <shudder> something from Symantec or other various utilities). On Mar 21, 2004, at 12:31 AM, Dr. Trevor J. Hutley wrote: > What are the symptoms of a messed up user database ? > How does this happen ? > What CAN we do about it ? > I think this could be very useful and helpful information for all Ti > (Al-)book owners, running OS X, if you have time to share it with us.