It's been some time that the Undo Close tab or Ctrl+Shift+T does not work and I am not able to recover even the tab I just closed. I have to manually open it again from history!

How can this problem be solved?

  • I tried this solution, but unfortunately, it's not working properly. I lost every opened tabs. It must be more complicated to restore tabs back.
    – hariprasad
    Jul 16, 2014 at 16:48

1 Answer 1


I noticed that by running Firefox as root (sudo firefox) I am able to do this, but once I come back to normal mode, it does not work again. So it occurred to me that the original problem may have been started when once in the past I executed Firefox as root.

It seems Firefox creates some temporary files and uses them to do these jobs like reopening closed tabs. Since in root mode, the owner of these temporary files is root, in normal mode it cannot overwrite those files and so the related features are disabled!

To fix this I ran this command to change all of the Firefox's config files' ownership to my user using this command:

sudo chown $USER:$USER ~/.mozilla/firefox/ -R

and then I restarted Firefox and it worked.

  • 3
    thanks, man. I suspected that was the problem. You are the only one google could find that gave a sensible and correct answer instead of the thousand threads saying "go to about:config blah blah" Aug 18, 2014 at 17:11
  • hey my friend i know i can do that by Right-click on + button on top of browser an use 'Reopen closed tab' but i don't know this shortcut, i don't think its related to root access however his problem was solved.
    – Sir-Sorg
    Dec 8, 2021 at 16:30

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