Sorry to hear about this problem. Did you notice any changes to other Firefox data such as history, saved logins, toolbar customization, or add-ons? If you haven't already, could you close out of Firefox and do a normal Windows shutdown and restart to complete any pending updates and release any file locks. If Firefox again starts up without your bookmarks, could you check the steps in the following article: [[Recover lost or missing Bookmarks]] ''Note: There isn't any way to roll back Firefox to an earlier version without making the problem worse, unfortunately.''