If you closed before restoring previous sessions they get cleared out. Only way to find them that I used was to go through the History queues to find them. This assume you didn't check your Privacy&Security boxes to clear out the data if you did this then they are gone.

I have lost 3.500 tabs, History keeps only the last 6 months. Until version Mozilla 54.0 you could change the extension of .bak file in .js and you could recover your data very quickly and easily. I wonder if: favicons.sqlite, places.sqlite, webappsstore.sqlite It could somehow help ??? webappsstore.sqlite has 106,000 KB may contain the information I am looking for. Same with places.sqlite, has 76.000 KB and favicons.sqlite has 27.000KB My lost information is about 12.000 KB. I have already made a copy of entire Mozilla after I closed accidentally and I opened. recovery.jsonlz4, recovery.baklz4, previous.jsonlz4 were already empty.

The places.sqlite file has your bookmarks and history. Usually, it's easiest to look at the history from within Firefox, but there also are external utilities such as the following if needed:

http://www.nirsoft.net/utils/mozilla_history_view.html

To avoid this problem in the future, you can set Firefox to always restore your previous session windows and tabs at startup. That's 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

In the Startup section, change from "Show your home page" to "Show your windows and tabs from last time"

bu.. said

I have lost 3.500 tabs ... My lost information is about 12.000 KB.

So probably you had most of those tabs open for a while. In your copy of sessionstore-backups do you have a recent upgrade.jsonlz4 file from when you installed Firefox 59.0.2?

favicons.sqlite => this contains icons for tabs I closed a while ago, perhaps because I have a bookmark to a page on the site

webappsstore.sqlite => this seems to contain "local storage" data for sites that use DOM storage

I viewed the contents of the files using this tool:

http://inloop.github.io/sqlite-viewer/

You also could check for earlier recovery.jsonlz4, recovery.baklz4, and previous.jsonlz4, and sessionstore.jsonlz4 files in a restore point. On Windows 7, this is integrated into the Properties dialog, so:

You can open your current Firefox settings (AKA Firefox profile) folder using 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, click the "Open Folder" (or "Show in Finder") button.

Double-click into the sessionstore-backups folder. Then use right-click > Properties > Previous Versions to check for shadow copies of the files. Use the Copy... button to save a file to a safe location for examination (do not replace a live file).

After you exit out of Firefox, the sessionstore.jsonlz4 file should be created at the main level of the profile folder. Then you can do the same search for that file using the same technique.

Find anything promising?

In the future I will downgrade and I will use version 53.0. 6 months ago I stopped the Mozilla automatic upgrade option. My latest upgrade file is from 27 august 2017 and is a .js file not jsonlz4 .

When I go into the sessionstore-backups, I come directly from the windows not from the troubleshooting information so I need to click option "Show hidden files, folders or drivers" to see Appdata.

jscher2000 you're genius, do you work for Mozilla ?? In properties I found recovery.jsonlz4 from last week. Thank you very much

The lz4 started in Firefox 56, so earlier versions can't use them directly. To decompress to JSON, see my tool here:

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

And no, I don't work for Mozilla. Or should I say, I don't draw any pay from Mozilla. ;-)

I was optimistic that I could save the tabs with the saved information. Not even for a second I didn't think I couldn't recover all the tabs. It's not the first time the impossible becomes possible. Everything is possible when you try, even if you try it for 10 hours. I hope for others to be easier, but it is certainly possible. That's why I'm using Mozilla. Thank You, again jscher2000. Kind Regards