Post a similar screenshot of the files in your sessionstore-backups folder in your profile folder. see screenshots

I wasn’t aware of this. I’ll take a look when back on my PC. (I’m on an ipad at present) Is this something the user has to setup, or does firefox do this up automatically? (hopefully the latter😀)

Here are the screenshots you requested. What am I looking for?

Yes, it's automatic, but it has been reset by restarting or browser updates which is why I make a copy of the folder. see old screenshot I assume your issue happened on the 14th. With Firefox closed, you can make a copy of the file with from the 14th(in your screenshot)and also the one from October. Then change the name of the newly copied file to sessionstore.jsonlz4. Remove the current file with the same name in your profile folder and then move the new file into the profile folder. Open Firefox and see if it restores your session. If the file from the 14th doesn't have the session you're looking for, then you can go back in time going through the same steps with the file from October. The 2nd screenshots is just an old example of the process.

Thanks for that. In this instance it wasn’t a major catastrophe, but it’s nice to know for future reference. I’ll give it a try and see if my ‘forgotten’ websites show up😀