"Thunderbird is already running" error every time I try to start Thunderbird, even if it is not running

I cannot open Thunderbird. The process isn't running, but when I click on the icon, I get the the following error:

Thunderbird is already running, but is not responding. To open a new window, you must first close the existing Thunderbird process, or restart your system.

I've tried the following:

Ending the task in Task Manager
Deleting parent.lock
Uninstalling Thunderbird
Uninstalling Firefox
Running Thunderbird in software "safe mode" and Windows safe mode

What can I do to fix this problem?

The problem looks more serious than expected. I do not see any Mail folder in my profile at C:\Users\your-username\AppData\Mozilla\Thunderbird. I think I lost my email.

Robert

Posted 2012-09-23T03:59:11.107

Reputation: 21

1I added your extra comment detail to the question. The path provided doesn't look right, Thunderbird is not in Mozilla normally. Where is the parent.lock file you deleted? And how were you able to end the task in task manager if the process wasn't running? – Paul – 2012-09-23T09:50:50.483

Answers

You said you've tried ending the task in task manager, but have you tried ending the process in the task manager?

Does it ever work correctly, for example the first time after rebooting your computer?

Celeritas

Posted 2012-09-23T03:59:11.107

Reputation: 7 487

While the steps you described seem inconsistent, the most likely cause is probably an inaccessible or missing profile. See the following documents for hints on this

I will update my answer with more details, when it becomes more clear, what you did exactly and which results you got.

Gurken Papst

Posted 2012-09-23T03:59:11.107

Reputation: 3 874

What I experienced yesterday must be a major bug in Thunderbird. I've lost all of my mail. The folder for my corresponding profile is completely gone in C:\Users\username\AppData\Roaming\Thunderbird.

Robert

Posted 2012-09-23T03:59:11.107

Reputation: 21

-1

Uninstall and delete everything to do with thunderbird, then reinstall, worked for me, lost mail, but it's all on gmail anyway.

Kieran Sulikosky

Posted 2012-09-23T03:59:11.107

Reputation: 1

-4

Download Revo Uninstaller and then uninstall Thunderbird with that. Then reinstall Thunderbird. Also use Win+E to start Explorer, then browse to C:\Users\your-username\AppData\Mozilla and delete the Thunderbird directory in there.

Oh, by the way, Windows has notoriously bad process management, so be careful not to mess with the operating system.

Jonathan Reno

Posted 2012-09-23T03:59:11.107

Reputation: 318

1Will deleting my profile erase my email and configuration settings? What do I need to do to back that up first? – Robert – 2012-09-23T05:04:08.453

The problem looks more serious than expected. I do not see any Mail folder in my profile. I think I lost my email. – Robert – 2012-09-23T05:15:59.577

@Robert Yes, this would delete all your mail and settings so I cannot recommend these steps. Jonathan Reno should have put in a warning at least. The use of Revo Uninstaller is questionable also. – Gurken Papst – 2012-09-23T10:54:17.280