This WAS absolutely great when it did what it was made for. Unfortunately, my onetab page has turned up empty and that means it isn't fit for its explicitly intended purpose.
Good idea, good attempt, but it's not worth trusting this add-on for anything more than casual usage.

Worst Add-on on Firefox (not necessarily applied to other browsers; maybe works well with others); it does not work at all; it won't budge a bit by reloading the expected one-page with all the tabs stacked.

Saves all Tabs in one window, kills all other windows without saving or even asking before closing them

Very useful addon but I have to uninstal it because it slowed down Firefox badly. What a pity. If it is fixed I would use it again.

OneTab is an extension to avoid. When it works it works great. Then you trust it. Then it lets you down.

Specific failure that I have seen several times: Several Firefox windows open with multiple tabs, go to OneTab Icon, Right click, OneTab->Send all tabs from all windows to OneTab. All windows disappear except for the OneTab window. Close out of Firefox, reopen. OneTab doesn't have those tabs that you just saved in it, neither does Firefox, you lose.

Great, until all your data disappears...

My laptop ran out of battery and stopped, crashing the system. When I rebooted, OneTab was empty. All my tab groupings? Gone forever.

What a pain.

I added 80 tabs to OneTab. After a moment, I clicked on Restore and everything disappeared. I do not have any tabs that have been open for about a year. They are not in the history of recently closed windows / tabs. They are nowhere. I lost a lot of valuable information for me :(

Broken. This is my favorite add-on but it has stopped working in a catastrophic manner and I just lost all of my tabs. The "bring all tabs into Onetab" function closes all the tabs and windows *but doesn't add them* to the one tab extension. It just threw away all of my tabs. This worked before firefox 57 and yes I am using the updated version. I even uninstalled, restarted, installed the latest version, purposely opened multiple windows with multiple tabs and tried again just to test it... only for it to fail again in the same way. Now I have to go through the history and manually find the 50+ tabs it trashed earlier and switch back to Chrome. They don't even show up under "recently closed". This add-on is essential to my workflow so Chrome is the only option now. tldr: Works perfectly for 1 window, fails epically at multi-window. Was a 5 star, now a 1.

Hasn't been working since the New Year. I tried removing and re-downloading it. I upgraded to the latest firefox today, and it's still not working.

I used OneTab for months! And now I find all my tabs lost. Without any crash. They're just missing and there's no recovery option. Sorry, this makes OneTab useless.

Just lost all my tabs after a crash. The OneTab list is totally empty. What a waste. Won't be using this again.

its happens again!!!!. on firefox onetab lost all my data. So onetab and firefox dont care about us users.

I installed One-tab after installing Firefox 57. I set up several tab lists and it worked OK. I then didn't use One-tab for a couple of weeks and all my tab lists have disappeared from One-tab.
Not impressed.

Microsoft shut down my PC for a critical update and lost all my tabs!

Lost all tabs randomly. I followed guides posted by the devs to recover, but didn't work. I loved this app, but I can't use it anymore after this has happened twice in 3 months. You are better off making a bookmark folder and organizing you tabs in that as it's much safer.

I've been using OneTab, it was great until I've lost all the tabs (300+ of them) suddenly. I'm not entirely sure why this happenned, my FireFox is version 48.02 as I haven't been able to update it since my Mac OS has become outdated. Maybe the OneTab has become too new for my browser? I now see the "file not found" page on my OneTab tab, and I can no longer see the icon of OneTab either on the toolbar or in the list of add on-s...

Lost all my tabs, it didnt just not work, it actively ruined my browser organization.