First, find your profile folder by reading this Then, copy the files sessionstore.bak and sessionstore.js to another folder such as your desktop. Close your Firefox and copy the sessionstore.js to the profile folder, and restart Firefox. See if your session was restored. If not, close firefox, proceed to copy the second file (the .bak one) to the profile folder, and rename it to sessionstore.js , overwriting the other file. Restart Firefox. If not any of these two files has your session saved, sorry.

You can check in the Firefox Profile Folder if there is a file sessionstore.bak from around that crash time.
If you find such a file then make backup copy elsewhere and rename the file to sessionstore.js

You can also try to open the about:sessionrestore page via the location bar to see if that works.

Thank You both. It worked like a charm!!!

Many thanks and hours of tedium saved.

Thanks again!

Colin

I have my app tabs back! Thanks a lot!

See also:

• App Tab Initializer: https://addons.mozilla.org/firefox/addon/app-tab-initializer/