Mozilla Firefox profile is the place where all the important data such as history, bookmarks, cookies, and password are stored. Profile folder contains most of the important data of Mozilla Firefox. Places.sqlite, key3.db, permissions.sqlite, search.sqlite, formhistory.sqlite are some of the important profile files of Mozilla Firefox. Most of the problems associated with Mozilla Firefox can be resolved by copying the files to a new profile folder. Mozilla Firefox makes it easier to recover the data from an old profile. If you are having any problem with Mozilla Firefox, instead of trying to find and fix the issue, just make a new profile and then copy the important data to the new profile. Before copying the data to the new profile, backup the existing profile folder in order to restore if any problem occurs. Also, try to copy minimal amount of file that contain important information in order to reduce the number of errors.
Click on the links below to know more about recovering data from an old Mozilla Firefox profile:
Recovering data in Mozilla Firefox 4 from an old Mozilla Firefox profile
Recovering data in Mozilla Firefox 3.6 from an old Mozilla Firefox profile
Recovering data in Mozilla Firefox3.5 from an old Mozilla Firefox profile