Hi velive, let's assume the file is in good shape. Does your Firefox normally restore your previous session automatically? In that case, try putting the file in two places, of course after you let Firefox shut down:

(A) Main level of profile folder

Replace the sessionstore.jsonlz4 with the one you want to use.

(B) sessionstore-backups folder

Replace the recovery.jsonlz4 with the one you want to use.

That way, whatever, Firefox looks for, it should find the file you want it to find.

Success?

Note that sometimes there is a problem where your old session gets embedded in an old session, which Firefox cannot extract properly. In that case, you can use a page of links extracted by my tool here:

https://www.jeffersonscher.com/ffu/scrounger.html

Hi Jscher

Thanks for your reply.

I did as you advised placing a file in each folder - so far as I can see it did work. But it looks like the problem is deeper - not quite sure what happened but it seems the session file I am looking for is gone. Very strange. I don't remember that happening before. I was able to restore from an older file about two weeks ago. Is there any other place firefox places session backups where I might look?

Thanks again.

Session history files are pretty easy to lose, but setting Firefox to restore your previous session automatically avoids most of the ways to accidentally replace the files.

Since your Firefox just updated, do you have a file named something like:

upgrade.jsonlz4-20200720193547

I think that number might vary, but the modified date should be within the past 72 hours.

Do you only have this profile folder if you check this by going up one level to the "Mozilla\Firefox\Profiles" folder ?

• C:\Users\<user>\AppData\Roaming\Mozilla\Firefox\Profiles\

Jscher, yes I do have one of those upgrade files. It is the file I tried to restore but the session is gone for some reason.

I think I can identify where the problem lies but I'm not sure if it can be fixed.

Something seems to have gone when I restarted after the upgrade; I saw the tab appear for the session restore; normally when I click on that tab I get to a window with a button to click to restore the session, but when i clicked on the window after the upgrade it was blank. Because it was blank I closed the tab and went to look for the "restore previous session" in options, but it was greyed out. I think it was because I closed the tab, seeing it was blank, that I lost the session?

I then closed firefox and moved the files around to try to get my old session back. When I restarted firefox - nothing!

I can tell that that "upgrade" file contains my old session somewhere because the file is big, about 80mb - but I think because I closed the session tab, I have lost the ability to access the tab information in that fil

Did you try to place this upgrade file as sessionstore.jsonlz4 in the main profile folder location to replace the sessionstore.jsonlz4 file created by Firefox with Firefox closed?

HI velive, normally closing without restoring is fatal, but I thought the upgrade file was a snapshot from before that point. If you run it through the Scrounger tool, does it extract any of the missing tabs? I'm not sure it will complete with an 80MB file. That's pretty big.

Thanks - that was my first time using the scrounger!

Turns out all my tabs show up there. Strange isn't it? So they are there but for some reason firefox can't see them, so I can't load them.

It's like something got broken during the upgrade.

So what is the easiest way now for me to restore all these tabs? I notice that scrounger has an option for "save uncompressed JSON" - do I use this option, then use then copy that file to the same two folders as before?

cor-el yes I tried that but for some reason it didn't work.

I now know from using the scrounger that my tab data is indeed saved in the file - firefox just cant access it for some reason!

So what is the easiest way now for me to restore all these tabs? I notice that scrounger has an option for "save uncompressed JSON" - do I use this option, then use then copy that file to the same two folders as before?

I think if Firefox doesn't restore the tabs from the compressed file, it also won't restore them from the uncompressed file.

Unless something quicker comes along, I suggest using the Save List button to save the page somewhere handy like your desktop. It's a web page you can open in Firefox. Use the links to open the tabs you need most right now. The others you can open when you need them.