I keep my settings on "restore previous session" upon startup; because I use several windows and tabs to organize work on different projects and my general workflow.

After the latest update. Firefox (I'm using developer edition for some reason) crashes upon startup. One of the crash notification windows had me open up in safe mode, which excluded my extensions. There (in safe mode) my previous session opened up and stayed open without crashing. I disabled a few extensions that I no longer use and closed several tabs to see if that would effect the crash problem. I then exited Firefox (I couldn't figure out how to exit safe mode otherwise) and reopened via the start menu. Firefox now opens to what is essentially a new session and I can't figure out how to open the previous one. I'm guessing it "refreshed"? Regardless, is there a way to recover my "previous session" or is it lost forever?