Step 1 would be to salvage your sessionstore files and make backup copies before exiting Firefox or making any other changes.

Open your active Firefox profile folder (personal settings folder) using

Help > Troubleshooting Information > "Show Folder" button

Copy all files that start with sessionstore to a safe location such as your documents folder.

Does the sessionstore.bak file look as though it has a timestamp of your last good session, or something later?

The sessionstore.bak file is created at every start of Firefox as a copy of the sessionstore.js file saved in the previous session to make it possible to restore the previous session via the History menu at any time during the current session.
So once you restart Firefox another time then that sessionstore.bak gets replaced.

You can try to restore a previous version of the sessionstore.js or sessionstore.js file.

• Right-click: Properties > Previous Versions
• http://windows.microsoft.com/en-US/windows7/Previous-versions-of-files-frequently-asked-questions

Darn, i restarted firefox after this happened and it says "there are no previous versions available", i thought windows automatically did "windows backup" I did backup the computer to DVDs pretty recently is there any way i can get it off of that?

on the sessionstore.bak file there is a website "host":".window.state.tx.us" that was up during my last good session.

Did you backup all sessionstore files?

You can try to copy this sessionstore.bak file as sessionstore.js to the current Firefox profile folder and check if there are History > Recently Closed Tabs/Windows available.

There are also ways to extract links from a sessionstore.js (.bak) file.

See the post(s) in this MozillaZine forum thread about extracting URLs from a sessionstore.js file. f=38&t=622036&start=60&p=12098147#p12098147

Hi, i have a sessonstore.js and sessonstore-1.js, do i copy all the saved .bak file to one of the .js and how do i do that and to which one?

Hi bncase, make sure Firefox is fully shut down. At the next startup, Firefox will look for sessionstore.js, so rename the new copy of sessionstore.bak as sessionstore.js. Then when you start Firefox, if it doesn't restore the session automatically, choose that option from the History menu.

Hi, i guess i don't have an old enough .bak file, it opened a previous session, but not the one i wanted (older), is there any way to restore with my computer backup DVDs?

Hi bncase, how long were you keeping the important tabs open? You may well have backups of sessionstore.js and/or sessionstore.bak which contain at least some of the tabs. You might be able to restore them to a different location and take a peek inside.

Another possibility is to try the "Previous Versions" feature. See: http://windows.microsoft.com/en-US/windows7/Previous-versions-of-files-frequently-asked-questions When you right-click either sessionstore.bak or sessionstore.js and choose Properties you may find files available on the Previous Versions tab. Since I find system restore to be somewhat unreliable, it's probably a good idea to back up any current files you might want to load again before restoring any of those previous versions. As always, make sure Firefox is closed before restoring, or your changes may quickly be overwritten.

I had those tabs for a long time, and i saved the sessionstore.bak and .js when you responded the first time, it was not old enough though. I tried to do the previous versions option, but it didn't find any, I thought windows backed up on auto, guess not.

Thank God! I guess i did have a previous version of .bak files I just checked the .js files, got all tabs back, Thanks for all the help!