It sounds as though you used the "Refresh" feature that removes all your add-ons and restores default settings, and creates a folder on your desktop named "Old Firefox Data".

I think it would be best to check with the add-on's author about how to restore the old data because each extension tends to do it a bit differently and I don't know whether it's safe or effective to drop in old files.

I didn't see an FAQ on this on their site:

• https://www.one-tab.com/
• https://www.one-tab.com/help

They do have a contact page:

• https://www.one-tab.com/feedback

If you had these tabs open for a long time, you might want to try to recover tabs from older Firefox session history files that were not yet hidden by OneTab. Usually you can find files from three or more recent updates.

In Old Firefox Data, double-click into your old profile folder, then into the sessionstore-backups folder. To preview the contents of a file, you can drag and drop it onto the following page, then click Scrounge URLs:

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

You can save the recovered URLs as a list of clickable links in an HTML page.

That tool is on my site, so please let me know if it doesn't work for you.

I created a script to pull data out of your old OneTab storage file. This is going to take a few steps.

Click into your Old Firefox Data folder, down into your profile folder, and then into the browser-extension-data folder and finally into the extension@one-tab.com folder. You should find a file named storage.js which contains the OneTab tab groups lists.

Drag and drop the storage.js file onto a tab in Firefox. It will be hard to read but you might recognize some URLs and titles.

Change the encoding the Unicode so that more characters can be recovered. To do that:

(menu bar) View > Text Encoding > Unicode

Then, the exciting part. Open the Web Console in the lower part of the tab using either:

• "3-bar" menu button > Web Developer > Web Console
• (menu bar) Tools > Web Developer > Web Console
• (Mac) Command + option/alt + k
• (Windows) Ctrl+Shift+k

In the blank line at the bottom of the console, paste this entire script and press Return to run it. If you've never done this before, Firefox may ask you to do something to prove you understand it is dangerous to run scripts from strangers.

/* To pull a list from OneTab storage.js */
var oData = JSON.parse(document.body.textContent);
var tabgroups = JSON.parse(oData['state']).tabGroups; 
var out = '<textarea style="width:95%;height:95%">';
for (var i=0; i<tabgroups.length; i++){
  var lbl = tabgroups[i].label || '(Unnamed group)';
  out += lbl + '\n\n';
  var urls = tabgroups[i].tabsMeta;
  for (var j=0; j<urls.length; j++){
    out += urls[j].url + ' | ' + urls[j].title +'\n';
  }
  out += '\n';
}
out += '</textarea>';
document.body.innerHTML = out;

That should replace the tab contents with a list of pages in each group. You can use the Import feature of OneTab to bring in each list you want to reload. If you want to bring them all in at once, you may want to delete the tab group titles in between the URL lists (otherwise those will create little useless groups when you import).

Hope that helps.

I did not try the first method but the second method worked. Thank you, much appreciated.

Hi Jessier94, the web console script method worked for you? Could you mark that one as the solution so when this comes up in a search people will see it at the top? Here's the link to it:

https://support.mozilla.org/questions/1216235#answer-1108012