I am running Mac OSX 10.5.8 and Firefox 3.6.13. Yesterday, after I had been on the internet multiple times, I opened Firefox and my Booksmarks toolbar and navigation toolbar were both empty. My booksmarks don't exist when I open the Organize Bookmarks window. My history is also gone. I cannot navigate using the backbutton. I restarted Firefox and there was no change; restarted my MacBook had no effect. I searched for similar problems and tried opening Tools > Add Ons> Extensions, but there is nothing on that screen, and the 'Find updates' button can not be clicked. It is not keeping me logged into pages that I have been previously logged into, but it does remember passwords. If there are other problems, I have not encountered them yet.