That session is probably gone. You can try the History or the browser cache (about:cache)

To avoid such issues you can (should) choose: Tools > Options > General > Startup: "When Firefox Starts": "Show my windows and tabs from last time" Session restore works more reliable if you choose that setting.

I have the same situation as the OP noted, but although I have the settings as the responder noted, it does not work. Whether my system hangs, shuts itself down, or I use File, Exit, my tabs are not restoring from the previous session. I am on version 3.6.6 of Mozilla Firefox, and Windows Vista Home Premium, SP2. Thank you for any assistance on this really irritating matter.

I had the same problem. I had to added on Tab Saver and so far its working.

In the address bar, when you first open up your browser, type in "about:sessionrestore"(without the quotes). That *should* help you out.

That's not a lot of help, corel. 'It's gone.' May 2012 and it's still happening, especially after a version upgrade; that's not anything like a crash, it's just an upgrade, handled by the user. But the programmers seem so preoccupied with their creation that they fail to notice that a close of one version and an opening of a new is just an ordinary operation to a user [if you're an administrator]. We expect stopping and starting to work, and our last sessions to be remembered over that 'great divide'. What's so radical about respecting a user's environment? Not pretty, Mozilla.