This is a 3 part problem I believe. First is that sometimes I lose the ability to restore tabs in that the restore prevision session option has been greyed out and is unusable. Usually I would go to the files and find sessionstore.js and .old and replace them using an old version of .bak to replace .js and .js to replace .old, but now with .bak seeming to be gone every time I lose my tabs I don't know where to go. The only new thing to replace it was sessionCheckpoints.json and I have no idea what that is, but upon further inspection it seems to carry old data from when I last had my tabs. Second is that this issue will occur at random with one night I will close everything normally and the next they will be gone upon bootup. Third what happened to the old system or am I just encountering an error? My specs for firefox: Version 34.0.5, extentions: none that involve tabs, but addblock, Classic Theme Restorer, youtube-mp3 converter, and quick translator. Thanks for any help in advance!