Firefox Restore Session displays empty pane without windows

This isn't Mac-specific, so I'm prepared to get yelled at, but I thought someone here might have the answer anyway.

I had a numerous windows and tabs open when Firefox crashed. Instead of displaying the Restore Session window at restart with the windows/tabs displayed, the pane is now empty. To be clear, I don't mean that when I restore them, they come up empty; I mean they don't even display in the RS pane. Unfortunately my drive for Time Machine wasn't connected to save them there.

I've rarely had success with the sessionstore.bak option. At this time, I did save the .bak file, but it appears too small to contain all the lost windows, which seems odd - usually it's the largest one. The largest file in the Firefox folder is places.sqlite (don't know what that is). It's the only one big enough (I think) to contain them.

If there's a means to manipulate these to display those windows again, I'd appreciate knowing. I'm not adept at this, so very clear instructions would be greatly appreciated. Thanks.

Also, Firefox hasn't been saving my browsing history lately, so I can't find the windows that way. I don't know if places.sqlite contains that history (and not the windows), and is corrupted. If anyone knows how I can get it to save my history that would be great too.

UPDATE: Sorry, I can't see how to delete the above posts. I resolve the missing windows problem.

If anyone can direct me how to get Firefox to show browsing history, I'd appreciate it.