Firefox has been quitting unexpectedly but this time all my history was erased and the back and forward buttons don't work. A red bar appears with the message: The bookmarks and history system will not be functional because one of Firefox's files may be in use by another application. Some security software can cause this problem. I was going to just delete Firefox so I downloaded Safari. Suddenly, Firefox came back to normal except for it still wouldn't save any history. So when searching on Google my recent searches weren't being changed to purple - that meant I wasn't able to know which items I had viewed already. After about an hour of Firefox working fairly well, it crashed all over again and once again I have the above message and no history.