It's a very good tool for saving the state of your tabs and then go back to them ,when you need. Very useful for IT jugglers.

For all of you who have problems after the September 16 update, I guess the solution is disable and re-enable it. No idea why it broke after the sept 16 update but it seems to a viable solution. Otherwise, OneTab is a wonderful extension that does exactly what it says. It's one of my most used extensions. Hopefull the OneTab team could help fix this issue.

For those who lost their data:
Just close and restart the addon.
(You don't even need to close Firefox.)

I've been using One Tab for a while, and I love it!! After the update on 16 Sept however, I opened my computer to find all the sites listed on my One Tab had disappeared, and the icon wasn't showing properly on the toolbar.
GOOD NEWS!! After I read some reviews, saying they disabled the add-on, restarted, then enabled it again, everything was restored!! Yayyyyyy!!
5 Stars!! ⭐⭐⭐⭐⭐
To all those users who had the same problem and bagged it out in a review, I suggest you try the above fix, and then change your review!! 😊

Superb addon. But after update it stopped working. I disabled it, restarted Firefox, then enabled it. So everything fine again!

Con la última actualizacion de septiembre, se atenuó el icono y no funciona. La solucion es desactivar la extensión, cerrar el navegador y al volverlo abrir aparece todo de nuevo. Años usandola y es perfecta esta extensión.

This is a great tool. With the updates mid Sept. 2020 its toolbar icon grayed out and the saved tabs was blank. Some people uninstalled and reinstalled and said they lost the links. Instead of that I disabled it, restarted Firefox, and re-enabled, and restarted Firefox - the icon and links were all back.

Awesome, I love this addon 😍

As far as the latest update, it basically removed the add-on from Firefox. I followed what Justin said from another review, but for Mac OS : /Library/Application Support/Firefox/Profiles/08nnu9pm.default/extensions > open "Extension@one-tab.com.xpi" with the Firefox application, it'll ask you to reinstall. Now the add-on will be back, and running normal.

發生什麼災難了？在重開 fx 後，記錄下來的網址全沒了……天啊啊啊啊
--- after bugfix
資料回來了！辛苦了！改回五顆星！

UPDATE:
I am updating again to 5 stars in good faith that the developer has fixed the issue. This really is a great add-on.

Original Review:
Loved this add-on until yesterday. Everything disappeared (page with my links, icon). From reading other reviews it appears that it will work again if I uninstall/re-install add-on, but big bummer to lose my tabs. I got to rely on it a little too much. Now I will know that it is much more of a temporary holding pen.

After reboot Firefox, button OneTab becomes inactive. https://i.imgur.com/Bp7uMtM.jpg Disabling-enabling helps, but before rebooting.
P.S. Thanks for the correction!

I have been using One Tab for more than a year and it's fantabulous. I don't know how I managed without it. Thanks!

Muy buena aplicación pero debería de tener la opción de sincronzar las pestañas guardadas en los diferentes navegadores donde se utilice onetab.

This extension is invaluable to me. I was afraid that all of my tabs were gone with the last update. As others have pointed out, simply disabling and reenabling the add-on should fix the problem.

Works well. Does the job. Lost the tabs once but who knows. As for people complaining about the latest update 16/9 you just have to disable and re-enable to app to function..

The last update has a bug. I solved it by deactivating the extension and activating it

I'm freaking out. I'm a dedicated OneTab power user. [Edit: Or was. I found out that Tab Stash can import OneTab data. At least I can restore my last bu.]

And it just died. Gone. Not in my right-click menu. Won't open in the browser, but Firefox does show the manage app page. Ugh, my last backup was four weeks ago. I'm crushed. So much research gone. That'll teach me.