OneTab is essential. However, as of Sep. 2020, it has a new bug: it disappears after the browser is launched, and you have to disable and re-enable to make it work. They need to fix this. Also, the developer could make it so much better, for example by allowing more ways to manage and display the tab list.

Broken OneTab? Add-ons Manager -> OneTab -> Toggling "Run in Private Windows" every time Firefox starts-up seems to re-enable the OneTab extension.

My biggest gripe with OneTab is the insistence of utilizing: "https://www.google.com/s2/favicons?domain=" rather than other options or even no favicon. Yes, I would prefer an option to not even waste resources on the favicons.

It broke on the recent Sept 2020 update, but following a suggestion to turn it off and on again under about:addons page actually fixed it. I've been using this for a few years and continue to love it despite this.

Great Addon, just lacking a dark mode. Please add it & save me from going blind at night xD

OneTab's icon keeps disappearing every time after browser restart.... I think it has started recently.... It is there, but transparent, or without an icon, then I have to go into Extensions - Disable - Enable again, then I have the icon, next time it is disappeared again...

Overall it's a good extension but I've had trouble getting my tabs back twice now. This ext would get 5 stars if there was the option to export automatically. As a developer, I don't see why this would be a difficult feature to add. After the first time, I started exporting my tabs periodically so if I did lose any then I probably could remember the most important links from recent memory. This time I lost all my tabs and the icon disappeared. From reading the reviews, I'm far from alone.

To restore my tabs I found a review with instructions. Go to ~/.mozilla/firefox/2tz4pwhp.default/extensions or a similar path in the Files GUI then double-click on a file called extension@one-tab.com.xpi . This opened up onetab, restored my lost tabs, and fixed the missing icon in my browser after giving permissions in the oneTab pop up in my browser and refreshing my OneTab open tab. I am using Ubuntu 18.04 LTS and Firefox 80.0.1 (64 bit). Hope this helps.

Update: This only fixed the problem temporarily. I had to follow the steps again after restarting my computer. An easier step, as was already mentioned in some reviews, is to simply go to Add-Ons in Open Menu (top right corner) and then disable OneTab by clicking the white circle in the blue oval. Click it again to enable OneTab and it should be working again.

Re-evaluating my review. The developers have been in contact and seem to have fixed the issue.
There might be a need for a automatic backup feature that makes a backup every week or perhaps prior to an update occurring in case something goes wrong. Many users lost very important info and I can't imagine what it was like for them!

OMG, I was so dependent on this add-on, it is a must, but for what I assumed it update auto and a lost more than 1000 tabs needed for work and researching, is there a way to recover them? Even onetab page extension isn't working.

Edit:
this is how I got it working on firefox on POP_OS!, got to "/.mozilla/firefox/mbmm1a9s.default-release/extensions/" on my home folder and double click on "extension@one-tab.com.xpi" file, then it opened in firefox and gave permission to the onetab notification and voilá, it restored all my tabs again!

now backing up the urls to a txt file in nextcloud using the export function

They seriously need a more robust solution for saving data or backing it up to Nextcloud or smth!

I am now very dependent of OneTab. It saves so much RAM and organizes all my open tabs nicely. To my horror this morning all my saved tabs were gone. After hours searching for a solution I find here in the reviews that the solution is to disable and re-enable the plugin to make it come back with all saved tabs. I will give 5 stars if this marvelous plugin could make automatic backup copies of all saved tabs in a simple, plain .html file that is available immediately in case of some failure either from the browser or the extension.

This was an indispensable add-on for me until today (16 Sept. 2020). Today's update (v 1.36) has broken OneTab completely. I can no longer save tabs, nor can I get the OneTab page to open. I am using Firefox 80.0.1 running under Windows 8.1 Pro x64.
I was able to revert to v1.29 (which still works) on a Windows PC, but only by first removing and then re-adding OneTab, which resulted in the loss of all of my stored tabs. The instructions at https://www.one-tab.com/firefoxRestore are evidently outdated, as the indicated "simple-storage" folder under Windows 8.1 Pro x64 is empty, regardless of whether Firefox is running.
Having learned from my experience with the Windows PC, I disabled updates on my Ubuntu PC. This appeared at first to have the desired effect. However, when I started Firefox again after rebooting the system, OneTab was missing completely. I haven't found any instructions for recovering lost tabs under Ubuntu.
I have made exports of saved tabs on both machines, but they are a few weeks old. OneTab doesn't appear to have an automatic backup facility, and since it is unclear where its data now resides, I see no way to implement one.
Update: OneTab is working again as of th e new version, 1.39 (see developer response below), so I am upgrading my rating to 4 stars. I especially applaud OneTab's efforts to require the minimum permissions needed, although I would caution users to check the setting for reading tabs in private sessions, which is enabled by default.
The add-in is so useful that I would give it five stars, if:
1. The instructions at https://www.one-tab.com/firefoxRestore were updated. In case anyone is interested, OneTab appears to now store its data in an SQLite db in a folder named "idb" under \storage\default\moz-extension+++1297484c-254f-45f9-a970-69c5c1cc0f50^userContextId=4294967295
2. It would add an automatic backup/export feature. The HTML export/import works very well. How much trouble would it be to automatically store the export file? This could be an option to be done on each update of the list.
Judging by the posts my web search turned up, this isn't the first time a bug has caused OneTab users to lose data. Regardless of the problem's source, I am sure that many users would be glad of some such insurance.

Hi, congratulations and thanks for a great and useful add-on. I use Firefox 78.0.2 and think to use OneTab in a long term. I need to know HOW to make a backup of the saved tabs and entire last status of OneTab in the case of accidents, system crash or just upgrade update to new Firefox version under other system user name. I am talking about Export / Import URLs since it don't preserve dates and other important data, plus that's a simple url's backup. I mean a way to create a TOTAL backup in order to restore everything in my last OneTab occurrence. PLEASE! is urgent to me! Thanks in advance.

Really useful to save multiple links to a single page for later use. It would be useful to have an UNDO button, for when one clicks on the toolbar icon mistakenly, then all the organised tabs (using Tree Tabs) are put in one page.

I really like OneTab but keeps disappearing from Firefox. I do not have that problem using it in Chrome.

Excellent extension for most common browsers. Missing feature of a cloud sync ability so One Tab info was shared across browsers is what keeps this from being 5/5 for me.

This review is for the PC version:
There have been many addons that have attempted to do something similar to what this addon does, but none do it quite so reliably and easily. This addon is very simple & intuitive to use, and I have very quickly become reliant on it. It does almost everything I need it to do: drag tabs between tab groups, allows duplicates in case I want a certain tab in more than one group, group locking so I don't accidentally mess my sorting up, group starring to make it easier to find at the top of the tab group list, naming of tab groups so I know what I've put where, the option to share tab groups as a webpage to quickly get lists of links to friends and relatives, the list goes on and on. The only thing it doesn't do, and the only reason this review is 4 stars instead of 5, is because there doesn't seem to be a way to manually sort the tab groups themselves. Adding a new tab group changes the order and that's annoying to me, but not nearly enough to stop using it. If this feature is incorporated into the addon, I'll change it to 5. Thank you so much for this wonderful addon! Excellent work! ♥

Works well on both Firefox and Chrome, and I haven't been bitten by the issues that other reviewers mentioned. I'm taking one star back because import/export drops all tab group metadata (name, star, lock), which strikes me as a strange and inexcusable omission.

Perfect extension, VERY useful, its like bookmarking BUT BETTER, although I did go into firefox's task manager recently and it was the process with the highest power draw somehow, even higher than all my other tabs like youtube