''locking this thread as duplicate, please continue at [https://support.mozilla.org/en-US/questions/1051900 /questions/1051900]'' PLEASE HELP!!!!! FIREFOX has deleted ALL my TABS. That is A LONG YEAR OF RESEARCH LOST for trusting this bunch of amateurs who have no clue as to how to run a company and offer NO customer service whatsoever!!! I tried renaming the sessionstore.bak to sessionstore.js as I read in the forums, and the right-clicked on sessionstore.js > Properties > Previous Versions, but it didn't work, the about:sessionstore.js is empty!!! One thing that I noticed is that my system has only saved VERY OLD PREVIOUS VERSIONS, but 2014 and even 2011!!!! Then i did a system restore to the closed point - two weeks ago, which is FAR TOO OLD, but better than nothing. Now Firefox DOES NOT START. It gives me a little error message saying that "Couldn't load XPCOM." Rather than constantly making USELESS updates to Firefox and forcing my computer to take them on every restart, Mozilla SHOULD spend some resources on debugging and customer services!!!!