This site will have limited functionality while we undergo maintenance to improve your experience. If an article doesn't solve your issue and you want to ask a question, we have our support community waiting to help you at @FirefoxSupport on Twitter and/r/firefox on Reddit.

Search Support

Avoid support scams. We will never ask you to call or text a phone number or share personal information. Please report suspicious activity using the “Report Abuse” option.

Learn More

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.

  • 7 cavab
  • 20 have this problem
  • 1 view
  • Last reply by sfhowes

more options

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 have to Ctl,Alt, Del to close Thunderbird.

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 have to Ctl,Alt, Del to close Thunderbird.

Chosen solution

Do you have a profile lock file in your profile folder? If so, delete it and see if TB runs properly:

http://kb.mozillazine.org/Profile_in_use#Remove_the_profile_lock_file

Read this answer in context 👍 2

All Replies (7)

more options

Didn't work

more options

Hang on close Hmmm, does it occur if you use windows safe mode with networking?

more options

No Mat, Never been in Safe mode.

more options
more options

I think I'm having the same problem (it's running but the main screen will not open). In safe mode, it does open! Does this suggest a solution?

Thanks!

more options

Seçilmiş Həll

Do you have a profile lock file in your profile folder? If so, delete it and see if TB runs properly:

http://kb.mozillazine.org/Profile_in_use#Remove_the_profile_lock_file