You may have corrupt sessionstore [v56] sessionstore.jsonlz4 file(s). Delete all sessionstore* files and the sessionstore-backups folder.

Type about:support<enter> in the address bar.

Under the page logo on the left side, you will see Application Basics. Under this find Profile Folder. To its right press the button Show Folder. This will open your file browser to the current Firefox profile. Now Close Firefox.

Windows: Show Folder; Linux: Open Directory; Mac: Show in Finder

Linux: Under the page logo on the left side, you will see Application Basics. Under this find Profile Directory. To its right press the button Open Directory.

Locate the above file. Then rename or delete it. Restart Firefox.

Don't delete the files if you need to rescue any data from them, just move them out of the profile folder to some location where Firefox doesn't look for them. You can try to read out their contents using this tool: https://www.jeffersonscher.com/res/scrounger.html

Hey Fred, I have already tried this solution and Everytime I reopen Firefox it brings up the previous session. I have completely deleted the file 3 times with no luck.

Hello jsteegs,

This is going to be a very, very dumb question, but I'll ask it anyway, just in case :

In Options => General => under 'Startup' :

Is 'Restore previous session' unchecked  ?

(sometimes it miraculously seems to check itself .... )

Unfortunately it is still unchecked.

jsteegs said

Unfortunately it is still unchecked.

Thank you for checking to see if it was checked, though.

If there are no crashes; Firefox still might think there was a crash. Would you give this a try and close Firefox this way :

3-bar menu button => Exit (Power button) or : Ctrl + Shift + Q

(if you already tried it - sorry .... )

I ended up uninstalling and reinstalling and that worked.

jsteegs said

I ended up uninstalling and reinstalling and that worked.

Well, how about that - well done  !

I was just about to suggest to change the value of a preference on the 'about:config' page and you just saved me the trouble  !

You marked my post as Chosen Solution - would you please remove that mark (click on the 'Undo' button to the right) and then mark your own last post as Chosen Solution  ?

Again : well done  !

I actually tried that as well last night. It seemed nothing I did would work. So last resort was to just start over.

Thanks for the help.

jsteegs said

I actually tried that as well last night. It seemed nothing I did would work. So last resort was to just start over.

Well, you sure did a great job  ! Must be a huge relief to finally have things back to normal.

(don't forget to mark your own post as Chosen Solution ....)