The files list I posted in the comment just above - is hard to read, let me try listing them again here:

previous.jsonlz4 1/5/2018 2 KB

recovery.baklz4 1/5/2018 15KB

recovery.jsonlz4 1/5/2018 15KB

upgrade.jsonlz4-20171206182557 12/13/2017 1,299Kb

upgrade.jsonlz4-20171226083017 1/2/2018 1,349 KB

upgrade.jsonlz4-20180103231032 1/5/2018 2KB

Did you check your history tabs to see if they were still there? Also did you check your Privacy&Security settings as by default I seen where the history boxes were checked and if you didn't remover them a restart would probably wipe those out.

Hi Westend,

My history seems to be all there.

Where do I check Privacy&Security settings?

Why are you concerned about those items?

I've discoverd the 'scrounger tool' https://www.jeffersonscher.com/res/scrounger.html

The file upgrade.jsonlz4-20171226083017 when put into that tool seems to have a lot of my previous session - but only as recent as 1/2/2018.

Might there be another backup file sa of 1/5/2018?

Can I copy that file into a sessionstore.jsonlz4 file, and where would I place it folder wist to get firefox to restore at least that sessoin?

OK, I found PRIVACY & SECURITY settings (under the OPTIONS selection)...

Under HISTORY: - I still have REMEMBER HISTORY selected

under ADDRESS BAR I have all three of these checked: - BROWSING HISTORY - BOOKMARKS, and - OPEN TABS

Can someone respond?

The upgrade.jsonlz4-20180103231032 file looks like the most recent, but the file size is really weird. previous.jsonlz4 is similarly odd.

Several days have passed, so it may be too late to use the "Recently Closed Windows" and "Recently Closed Tabs" lists. These are available on:

• (menu bar - tap Alt to activate) History menu
• "Library" menu button > History sub-menu
• optional "History" menu button

Those should show up to 3 closed windows and up to 10 closed tabs per window.

Regarding using any other .jsonlz4 file in place of sessionstore.jsonlz4, you can make the substitution as follows:

(1) From inside Firefox, open your current Firefox settings (AKA Firefox profile) folder using either

• "3-bar" menu button > "?" button > Troubleshooting Information
• (menu bar) Help > Troubleshooting Information
• type or paste about:support in the address bar and press Enter

In the first table on the page, click the "Open Folder" button. This should launch a Windows Explorer window listing the various files and folders in your profile.

(2) Leaving that window open, switch back to Firefox and Exit, either:

• "3-bar" menu button > "power" button
• (menu bar) File > Exit

Pause while Firefox finishes its cleanup -- these changes should occur:

• recovery.jsonlz4 is moved from the sessionstore-backups folder to the main level of the profile folder and renamed to sessionstore.jsonlz4
• recovery.baklz4 is deleted from sessionstore-backups

(3) Once Firefox has stopped updating things, while viewing the main level of the profile folder, rename sessionstore.jsonlz4 to OLDsessionstore.jsonlz4

If you see an older sessionstore.js or sessionstore.bak file, move it somewhere else or delete it.

(4) Copy in the other file you want to restore, and rename it with the name appropriate for its format:

• Uncompressed .js file => sessionstore.js
• Compressed file => sessionstore.jsonlz4

(5) Start Firefox and it should read the swapped in sessionstore file and restore whatever was in the substitute file; if you do not have Firefox set to restore your previous windows and tabs automatically, use History > Restore Previous Session (or menu button > Restore Previous History)

Any luck?

You said (3) Once Firefox has stopped updating things, while viewing the main level of the profile folder, rename sessionstore.jsonlz4 to OLDsessionstore.jsonlz4

The only sessionstore.jsonlz4 I have is in this folder: C:\Users\matt\AppData\Roaming\Mozilla\Firefox\Profiles\5120jgru.default\sessionstore-bakups\sessionstore.jsonlz4

Is 'sessionstore-bakups' what you meant by the main level of the profile folder ?

=======

You said (4) Copy in the other file you want to restore

The most recent, and with the largest amount of data is: upgrade.jsonlz4-20171206182557 12/13/2017 1,299Kb

Can this file be copied into sessionstore.jsonlz4 ?

(I assume it cant be copied as sessionstore.json?)

Should I put it in 5120jgru.default, or, into 5120jgru.default\sessionstore-bakups\

The main level is:

C:\Users\matt\AppData\Roaming\Mozilla\Firefox\Profiles\5120jgru.default\

After Firefox closes, it should create sessionstore.jsonlz4 in that folder.

So that is the file you need to replace so Firefox takes the substitute file at the next startup.

Since you want to use a .jsonlz4 compressed file, use the .jsonlz4 extension.

(I don't know why there is a sessionstore.jsonlz4 file in your sessionstore-backups folder.)

I just realized I looked at this folder while Firefox was still running. Is that perhaps why there was no sessionstore.jsonlz4, or, sessionstore.json in the main level profile?

Does firefox use either sessionstore.jsonlz4, or, sessionstore.json (depending on which it finds) to load for last session?

So, I can use either the 'previous...', ' upgrade....', or , 'recovery...' files to load the 'sessionstore...' file?

When Firefox closes, it creates sessionstore.jsonlz4 at the main level, and it gets rid of recovery.jsonlz4 and recovery.baklz4. At startup, Firefox first looks for sessionstore.jsonlz4, second, it probably looks for recovery.jsonlz4.

You could try any file you like.

This file is more recent (Dec. 26) versus Dec 6 of the slightly lesser upgrade file.

• upgrade.jsonlz4-20171226083017 01/02/2018 1,349 KB
• upgrade.jsonlz4-20171206182557 12/13/2017 1,299 Kb

So best would be to use upgrade.jsonlz4-20171226083017 and copy this file as sessionstore.jsonlz4 to the main level where the sessionstore-backups folder is located.

Note that sessionstore.jsonlz4 should be at the main level and not in sessionstore-backups. It will only be in sessionstore-backups if you placed the file there yourself and you can remove the sessionstore.jsonlz4 file from that location.

Recently closed tabs expire in about two weeks, so you might still have some available with the upgrade.jsonlz4-20171226083017 created on January 2th.