Firefox crashes a lot, and usually restores the session. However, today, Firefox crashed, and then restored a damaged session - when the "we're having trouble restoring your tabs" page came up, half of the windows had no tabs in them. Looking at the contents of the sessionstore.js, it appears that those windows had their recently closed tabs saved, but not their currently open tabs. Also, the sessionstore.bak file had been overwritten less than a minute before the new sessionstore.js, and contained the same damaged data.

Is there some way to put a delay on the backup of the sessionstore file, or cause firefox to create multiple backups in sequence? With the current behavior that I'm seeing, the backup is useless to me, since it contains the same information as the latest session.