I'm not too sure about the OSX Operating System as I am a hard core Windows fan, but I do know that Firefox stores what is called a "Profile" for each user of Firefox. When you restarted, Firefox either didn't load your profile, or your profile was somehow deleted. Under Windows the profile is here: C:\Users\"Your User Name"\AppData\Local\Mozilla\Firefox\Profiles I do know that OSX and windows have almost the same folder and file structures only named differently. Check to see if your profile still exists. You may have to enable being able to view hidden file and folders. Also, your bookmarks and settings for browsers is usually located here in Windows: C:\Users\"Your User Name"\Favorites. Firefox stores all bookmarks, settings, etc. here usually. I'm not sure where it will be in OSX. but I'm assuming OSX has a favorites folder of some sort. You may have import all your settings and all that into Firefox if the data is still there. My guess is, Firefox lost the links to this data, or the links were deleted or corrupted on restart.

Can you let me know if your profile still exists? Use Recover important data from an old profile to find it.

If you use the Time Machine then you can also try to restore files there.

• http://kb.mozillazine.org/Profile_folder_-_Firefox