Firefox
Profile collison
Sometimes, firefox fails to load, giving an error such as File:Http://kb.mozillazine.org/images/CloseFX msg.png.
The solution is to delete the files lock and .parentlock in the afflicted user's profile directory. The profile name is a garbled mess, for example looking in a location such as ~/.mozilla/firefox/fdsfh385.default/ should show the files.
Typically, this is caused by a machine crash or strange profile conflicts from logging onto multiple machines at once and running firefox multiple times.
Grey buttons, no bookmarks
Haven't quite figured out why this happens, but sometimes firefox gets greyed out back and forward buttons, google search bar stops working, bookmarks vanish, and the address bar fails to update.
Solution: Delete places.sqlite and places.sqlite-journal. Firefox will regenerate non-corrupted ones from the backups.
Won't Start
If firefox fails to start, and does so silently, check to see if the process is running. If it is, kill the process and try again. If it still fails to start, but runs, there's NFS lock issues with einstein. This is a known problem with NFS home directories, but not sure why. The solution appears to be to restart NFSD on einstein.