Did you check "History -> Recently Closed Windows/Tabs" ?

Note that best is to use one of these to close Firefox if you are currently doing that by clicking the close X on the Firefox Title bar, especially if you have multiple windows open to prevent losing tabs in unnoticed windows.

• "3-bar" menu button -> Exit (Power button)
• Windows: File -> Exit
• Mac: Firefox -> Quit Firefox
• Linux: File -> Quit

You can try to restore a recent upgrade.jsonlz4-<build_id> when available or use a utility to browse Windows System Restore points to see if you can find a recent sessionstore.jsonlz4 file.

You can copy a file from the sessionstore-backups folder to the main profile and rename the file to sessionstore.jsonlz4 to replace the current file with Firefox closed.

• make sure to backup the current sessionstore.jsonlz4

You can look at this tool to inspect a compressed jsonlz4 sessionstore file.

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

You will normally find these files in the sessionstore-backups folder:

• previous.jsonlz4 (cleanBackup: copy of sessionstore.jsonlz4 from previous session that was loaded successfully)
• recovery.jsonlz4 (latest version of sessionstore.jsonlz4 written during runtime)
• recovery.baklz4 (previous version of sessionstore.jsonlz4 written during runtime)
• upgrade.jsonlz4-<build_id> (backup created during an upgrade of Firefox)

Thank you! Thank you! Thank you! I Love You It worked perfectly. Thank you

Oops, all my lost tabs have reappeared but my Bookmarks Toolbar has disappeared. Are they related? How do I restore the Toolbar? Thanks.

Restoring tabs shouldn't affect the Bookmarks Toolbar. Do you still see the (empty) Bookmarks Toolbar or is it completely gone ?

See:

• https://support.mozilla.org/en-US/kb/bookmarks-toolbar-display-favorite-websites

Also make sure that the "Bookmarks Toolbar Items" control is positioned on the Bookmarks Toolbar.

• https://support.mozilla.org/en-US/kb/customize-firefox-controls-buttons-and-toolbars

The Setting for the Toolbar is: Always Show The toolbar is there. It appears that it has reverted to the original default settings. I have just three bookmarks on the toolbar: Most Visited Getting Started Latest Headlines

Are you still using your original profile ?

• https://support.mozilla.org/en-US/kb/recover-user-data-missing-after-firefox-update

Do you have backups in the bookmarkbackups folder?

• https://support.mozilla.org/en-US/kb/restore-bookmarks-from-backup-or-move-them

The name of an automatically created JSON bookmarks backup in the bookmarkbackups folder includes a total item count (folders and separators included) and an hash value to prevent saving the same backup more than once. You also see this count in the Restore menu drop-down list.

• bookmarks-YYYY-MM-DD_<item count>_<hash>.jsonlz4.

In my profile folder I have a bookmarkbackups folder that has a file from 12/22/22 (which is before the problems started). Can I restore from it? Copy/Paste/Rename, something simple like that :-)

I have a file: bookmarks-2022-12-23_79_Cs5yh+1fhE0taKAzUN91lg==.jsonlz4 Which is before the problem manifested.

You can restore this JSON backup in the Bookmarks Manager (Library) like explained here:

• https://support.mozilla.org/en-US/kb/restore-bookmarks-from-backup-or-move-them
• Bookmarks -> Manage Bookmarks -> Import & Backup -> Restore

WOW! I am back to normal. That was great. They are all there. And so easy. Thank you so much cor-el. Again.