I have recently been getting an error message when I open Firefox saying "The bookmarks and history system will not be functional because one of Firefox's files is in use by another application. Some security software can cause this problem". This has been happening since I clicked on a mail in Mail to unsubscribe from a spam/phishing mail list, which seemed to result in me installing Firefox Private Browsing, which I had never subscribed to. I have tried uninstalling Private Browsing but there is no way of doing that. I have even uninstalled and then re-installed Firefox completely but I still have the same problem. Because of the problem I have now lost all my bookmarks and history, and am unable to create new bookmarks and history. I have been on the help forums and seen that I can Disable Private Browsing by going through my anti-virus (Avast), which I have not yet tried because what I would really like to achieve is uninstalling and not having Private Browsing on my Start menu, rather than simply disabling it. Anyway, would disabling it solve the bookmarks and history problem ? Can anyone give me the solution ? Thanks. As you may gather, I am not very techno so you would have to give me the idiot's version of any instructions or advice.