The question Tor Browser Says Firefox is Already Running is very related to this issue but I couldn't add a comment as I am new to this site.

I have noticed ever since 3.6.4 that although the Tor connection is made and can be used by other configured software. The Tor Browser Bundle Firefox will not start up first time. I can run Thunderbird/birdie using the connection and it works fine. Looking at the process list it says that tor.firefox is running (but it can't be seen). The only way to get it to open is to kill the process and restart.

I was hoping that there was a bug that would have gotten fixed by 3.6.5 but it wasn't. It recently takes about 5 tries to get it started eventually.

As advised in this other thread Tor Browser Bundle will run on a completely different disk and away from any system files. Even regular FF configured to use Tor will run fine on top of the tor.process.

Out of a unsubstantiated suspicion I do not use any other connection over such a process until I get Tor Browser Bundle to run properly and verify the connection is correct.

I rarely use a couple of plugins and disabling or deleting them and reinstalling the bundle had no effect on this behavior.

I don't recall this ever happening before 3.6.4 and 3.6.5 made no difference.

  • Where did you unpack the browser bundle to? And what version of windows?
    – IAmNoone
    Commented Sep 25, 2014 at 7:25
  • Did you try to run TBB as administrator? Commented Sep 25, 2014 at 14:44

3 Answers 3


This is caused by a bug that has received a workaround with the new Tor Browser 3.6.6. I used to have this problem with 3.6.4 and 3.6.5 but it seems to work fine now.


Usually this means that you have Firefox already open. You should open your task manager and kill the task.

If that doesn't work, you should try putting the file in a different folder (i.e., in the Desktop instead of Applications.

I hope this helps.

  • When an instance of Firefox uses certain profile it locks it (on *nix lock symlink in the profile directory - for TBB tor-browser_en-US/Data/Browser/profile.default) and does not allow to run a new instance. In such a case Firefox shows a pop-up with error message. --- Using a different directory should not make a difference unless the profile is somehow erroneously shared. Commented Sep 27, 2014 at 11:14

Tor browser is a Firefox at it's heart, so the well-known pain in the ass called "profile lockdown conflict" and a bit less common "neighbor process" case(your one) are very common. To avoid it - create multiple profiles in firefox, one by one(close the FF, create a new profile, launch FF with it, close FF) acting from the same user - it will make some profiles for you. After that, being started from this user - any firefox will show you a profile selection dialog, and no such conflicts will be possible. Or - if you need a one-click shortcuts - use a profile selection from a command line, create profiles in exact the same way I've described above. I'm using TBB, FF and FFDE - no problems so far for 3+ years

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