Hi, I can address a couple of things. I do not think your install worked as well as it should have due to not saving your tabs from November. If possible a clean install would be best.

Sorry am away from my site and do not have my notes to address to o much.

You may want to use something like this : https://addons.mozilla.org/en-US/firefox/addon/tab-session-manager/ Keyword for search is Tab Session Manager then enter to display a list.

This should provide you with some info : https://support.mozilla.org/en-US/kb/recovering-important-data-from-an-old-profile

When need more info let us know.

Just a hunch, the manner you used to get back to Quantum may have been the cause of losing tabs data saved between November when your reverted to an older version of Firefox and now when you "dropped" your Profile files into Firefox 60.

If you still have that old computer try updating to Firefox 60 and see if your tabs data survives the update from whatever your were using in the interim. If it does, try using those files from your Profile in the new computer.

My thoughts are that Mozilla usually provides a smooth transition during updates, where no data gets lost; but going back isn't as smooth and some users find that they lost some data by reverting to an older version. But by not updating from an older version and just using the files from the older (reverted) version, Firefox doesn't realize that the new installation is actually an "update" for the user and then that user then has to deal with lost data. There were a few "toggles" that may not have gotten reset by reverting and then not "updating" a 2nd time.

Plus updating to Quantum Firefox 57 back in November, the reverting to "Legacy" or Australis Firefox 56 (or even earlier), then copying that Profile to a new Firefox 60 installation sure sets the stage for having problems - jumping over 58 and 59 which did get some 'heavy' changes, IMO.

As far as recovering your tabs look for a folder named sessionstore-backups and look at the Modified date on the JSONL4Z files in that folder. As far as reading those files goes, I have no idea how to do that - if you find files that are dated appropriate to the data you are looking to retrieve. I think those files can be read by Firefox via the built-in Developer tools, but I am not familiar with those "tools". https://developer.mozilla.org/en-US/docs/Learn/Common_questions/What_are_browser_developer_tools https://developer.mozilla.org/en-US/docs/Tools

Support contributors who are familiar with those tools might be able to help you later in the day - working hours into the evening hours in Continental USA time zones.

I managed to get the .mozilla directory and the ESR firefox from my old computer to my new. And I can use that version to see all my tabs. It has upgraded itself to 52.8.0, and is working ok.

But I'd like to get onto the main line version. I download and install that (apt-get install), and when I bring that up, again it discards all tabs since November.

(Of course I saved .mozilla before doing this, and when I restore it, the ESR version works again. This version does not support the tab session manager)

My guess is that starting that Quantum release up in November read the status of the tabs at that point, and any new version I install looks at that instead of what the ESR has. So it's my further guess that if I remove all the relics of that installation, and try again, it will convert the tabs as of now. What would happen, for example, if I removed everything whose name looks like sessionstore except sessionstore.js? It's been my experience that the ESR and earlier releases relied only on that file.

What's What in the Profile :

• bookmarks and history: places.sqlite
• bookmark backups: compressed .jsonlz4 JSON backups in the bookmarkbackups folder
• cookies.sqlite for the Cookies
• formhistory.sqlite for saved autocomplete Form Data
• logins.json (passwords) and key4.db (58+) or key3.db (57 and older) (decryption key) for Passwords saved in the Password Manager
• if you only have key3.db then make sure to remove an existing key4.db
• cert9.db (58+) or cert8.db (57 and older) for (intermediate) certificates stored in the Certificate Manager
• if you only have cert8.db then make sure to remove an existing cert9.db
• persdict.dat for words you added to the spelling checker dictionary
• permissions.sqlite for Permissions and possibly content-prefs.sqlite for other website specific data (Site Preferences)
• sessionstore.jsonlz4 for open tabs and pinned tabs (see also the sessionstore-backups folder)

• https://support.mozilla.org/en-US/kb/recovering-important-data-from-an-old-profile
• http://kb.mozillazine.org/Transferring_data_to_a_new_profile_-_Firefox
• https://support.mozilla.org/en-US/kb/profile-manager-create-and-remove-firefox-profiles

I got it to work by removing all files that seemed like they were part of the November upgrade under my profile directory. It took several tries, but anything with "upgrade" in its name was removed, and then anything with lz4 in its name.

Apparently the browser when it doesn't have evidence of upgrades uses the old mechanism; but if it finds something that indicates a newer version was installed, ignores those old mechanisms. That makes sense, and that may very well be how I would have designed it if I had been the one.

So this issue can be closed. I don't see a way to do that from this screen.