Hi AuntEva, Firefox 52 ESR has reached its "end of life" and that's why it was replaced with the new Extended Support Release, Firefox 60 ESR. Due to technology changes, many extensions were never updated to work with Firefox 57+ and you'll need to find replacements for those.

To restore your previous Firefox session, you can use the menu command:

• "3-bar" menu button > Restore Previous Sesssion
• (menu bar) History > Restore Previous Sesssion

That's only for the immediately previous session, though, it doesn't go back further than that. To avoid loss of Firefox sessions, you can set Firefox to start up automatically with your tabs from your previous session. It's the very first thing on the Options page:

• Windows: "3-bar" menu button (or Tools menu) > Options
• Mac: "3-bar" menu button (or Firefox menu) > Preferences
• Linux: "3-bar" menu button (or Edit menu) > Preferences
• Any system: type or paste about:preferences into the address bar and press Enter/Return to load it

Now, what about old sessions you saved with the Session Manager extension? They are in a folder in your profile folder, so you can convert them to an archival web page of links and use that to re-open those tabs. Here's one way to do that:

(1) Open your sessions folder

Start from Firefox's Troubleshooting Information page. Either:

• "3-bar" menu button > "?" Help > 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, on the Profile Folder row, click the "Open Folder" button. This should launch a new window listing various files and folders in Windows Explorer.

Find the sessions folder and double-click into it. If you see a folder named sessionstore-backups that is Firefox's own folder, not the one created by the old Session Manager extension.

(2) Load the converter into a tab

I have a tool here:

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

(3) Drag, drop, and Scrounge

To convert a file from your sessions folder to a page of clickable links, position the Windows Explorer window so you can see the white box on the converter page and drag and drop a file there. Then click the Scrounge URLs button.

You can save these web pages somewhere convenient for future reference.

If you want a new add-on to handle session management, here are two that many users like:

• https://addons.mozilla.org/firefox/addon/session-sync/ -- stores your session tabs as bookmarks, taking advantage of Firefox's automatic bookmark backups and sync
• https://addons.mozilla.org/firefox/addon/tab-session-manager/ -- stores your session tabs in a database in your profile folder

Thank you very much. I managed to find a setup file for 52.9.0esr but from what you write it sounds like I'd better migrate very soon. The suggestions you offer will come in handy at that time. I think I'll set up another copy of firefox (dangerous, I know) and migrate over the next couple of months (so your scrounger {thanks!} doesn't go away before I do this. Thanks again!

Note that is isn't safe to downgrade a profile used by recent Firefox version to 52 ESR. Some database files have been upgraded to newer versions and are no longer compatible. Favicons are stored in favicons.sqlite and not in places.sqlite. There are also changes to local storage (storage folder in the profile folder).