For years, this add-on has suffered from a persistent bug: after an unknown background action, the "Open" button in the Saved Sessions Manager suddenly stops working. I’ve spent several hours troubleshooting, but the technical root cause remains elusive.

Here is what I have established so far:

Profile Corruption: Something is corrupting the user profile. Creating a fresh profile resolves the issue, but only temporarily.

No Add-on Conflicts: I have 100% ruled out conflicts with other extensions.

Clean Install: The issue is not caused by leftover data; a full, clean re-installation of Firefox did not fix it.

The most important point: While I cannot pinpoint the exact trigger in the code, I am able to reproduce the bug reliably. I am happy to assist with further questions or testing.

Fundamentally useless. 'Open' button for saved tabs cannot be coaxed to work, at all. F$^# this piece of s#$^%.

Once every few months, it randomly dedices to delete all my sessions and reset my settings. Absolute trash.

This extension used to be great! I donated a few times. Today I had to force restart my computer and Firefox came up with no tabs! I checked the Tab Session Manager and the last save it had was from over a year ago! I guess the auto save doesn't work any more and all the sessions I did have saved are gone. This extension is totally broken now.

STILL DEAD!

All pin and save tabs lost. I removed this scrap

Es öffnet die Tabs doppelt. Duplicates the saved windows and doubles up on my memory usage. Ich habe gewartet ob es ein Update gibt, aber als letztes Update steht 28.03.2025

Currently, this add-on just duplicates the saved windows I had open and doubles up on my memory usage. It doesn't seem like this is needed anymore with Firefox's native support.

WARNING!!!!! If you have more than 10 tabs open, this will overload the extension. As a self-defence mechanism, the extension deletes the saved session.
It cannot import a saved session containing more than 10 tabs.

Worked great for a long time, but in the last month or so, the "autosave sessions" feature hasn't worked at all. I've checked my sessions to try to find windows/tabs I wanted to go back to, and the last thing saved was over a month ago even though I know I had Firefox at least set to restore previous windows. But this extension didn't save ANYTHING over the last month+ even though I had it set to do so, so that feature doesn't do anything anymore apparently. I've lost dozens of sessions due to either a bug or recent updates, but either way this is bullshit.

Garbage. Stopped working months ago. Literally never saves tabs. Don't waste your time. It also randomly deletes your sessions. Don't be tricked by the good reviews btw. They're old reviews from years ago when it actually worked.

does not work with Firefox 'tab groups'

I loved this extension, it did exactly what I needed it to, but the "open" button has suddenly stopped working. I tried removing and reinstalling the extension but I have no way of opening sessions anymore. I can only click on each link one by one. If this is fixed, I'll revise my review.

Documentation / Readme is insufficient. Cannot see what the Tab Session Manager is actually supposed to do and how to use it. What makes it worse, is the author's poor command of the English language. In Settings, file paths are not shown, and apparently cannot be set. All in all the whole thing seems too complicated to me. On top, when experimenting to make sense of the extension, it repeatedly crashes and takes the browser with it. A waste of time.

Does not even appear on the toolbar or anywhere else - so no idea if it actually works or not. About to uninstall and find something else.

Did not save my fucking tabs.

Destroying my tab groups every launch. All Tab Groups need to be recreated, all tabs need to be readded to their groups. Disabled until this is supported.

Not restoring previous.jsonlz4

On two different ff versions 91.9.1 and 115.20 it randomly deleted ALL sessions, on one ff i lost a sessionwith 2000 tabs and on the other 1800 tabs, backup is disabled by default, no other backups are kept and recovery is possible only if you have all your history from the past 6 months. evrything else is pretty good.

used to work but recently after the notorious Firefox update it's now broken and author does not respond.