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.

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 sessionstore [v56] sessionstore.jsonlz4 file.

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

Sorry. Do Not move or rename the file. Just use the tool as instructed.

If you use the Time Machine or other backup then try to restore the sessionstore.jsonlz4 file(s) from this backup.

• http://www.apple.com/support/timemachine/

Thanks very much FredMcD, that's got most if not all of the tabs i had open (yet to do a complete check but looks like it got them all).

Thanks Cor-el, i didn't use TM or another backup, i am over due though so i will do it very soon.

bit of an update for anyone that reads this thread in the future, i told https://www.jeffersonscher.com/ffu/scrounger.html to "Save List (HTML with Links)" and then opened it with Text Edit (OSX) and it's showing what looks to be a complete list of links.

I use an add-on that makes backups of my user profile, Just In Case. Unfortunately, it is not compatible with the current Firefox.

Every now and then, open the profile folder and create a copy of the current profile as is to another location on your hard drive. This way you will have a backup.

If you do this each day, you will not lose much data. This should be done with Firefox Closed.

Note: In case you need to restore from these backups, you may need to overwrite old or corrupted files.