I was working on a project with many open tabs (30+) when around 19:30 firefox crashed (which happens quite regularly when that many tabs are open, got used to it). After the crash this time the tab about:sessiorestore didnt come up. Just my small tab on the left side which always stays there (my mail) what i told firefox to do (dont know the name for that in english cause i have dutch firefox) plus a tab with www.Qvo6.com, which also openend in a second window , while i had had only 1 window open. Typing in "about:sessiorestore" myself, the list appeared empty. Lost all of my open tabs. The menu options "Restore last session", "Recently closed tabs" and "Recently closed windows" were all grey and thus empty. I never had this before, it always worked. A lot of work is gone. The additional problem is that i cannot retrieve my tabs from my history cause one of the open tabs was a session restore tab itself, with a session containing a tab with in there also a session restore tab which i all wanted to be able to recover cause that were sites i needed for other important projects i was working on. The third level session restore was longer than 8 months ago, so those sites are not in firefox history anymore (why..? :/) and other, more recently opened pages are SO hard to find back in the thousands of sites i visited in the past 8 month that checking each site will be undoable, since i dont even remember the exact name of opened sites. I hope you can imagine the size of the problem to me here. So: is there a file where different restored sessions are stored in? cause apparently different sessions can be saved and retrieved. Retrieving a session restore within a session restore - as i just described - did work before. Until you lose em all, like now. Can sync or xmarks help me maybe..? I really hope you can help me. Lots of effort and time is lost here. Love to hear from you. PS can this be related to bug 651803 which i reported before..? ("Recently closed tabs" staying empty) Oh and I installed and uninstalled a toolbar which changed the startpage to Qvo6.com but even after that, the last crash session restore still worked. Just thought i'd mention it cause Qvo6.com opened two windows while i had had only one open. Maybe that influences start pages after crash like session restore.