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.

Avatar for Username

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

This thread was archived. Please ask a new question if you need help.

App telling me that a copy of Thunderbird is already open but it's not. iMac El Capitan

  • 1 reply
  • 1 has this problem
  • 2 views
  • Last reply by Zenos

Geggsy125
Geggsy125
more options

iMac 27" El Capitan (10.11.6 (15G31)) Thunderbird 52.3.0

I am unable to open Thunderbird as it is telling me that "A copy of Thunderbird is already open. Only one copy of Thunderbird can be open at a time" (see image).

There is no copy open.

When I open the "Force Quit" dialogue box Thunderbird is not showing there as an option. I am unable to open the app and access any email.

I have tried to upload a jpeg of the warning box but the site is not uploading the image for some reason!!!

iMac 27" El Capitan (10.11.6 (15G31)) Thunderbird 52.3.0 I am unable to open Thunderbird as it is telling me that "A copy of Thunderbird is already open. Only one copy of Thunderbird can be open at a time" (see image). There is no copy open. When I open the "Force Quit" dialogue box Thunderbird is not showing there as an option. I am unable to open the app and access any email. I have tried to upload a jpeg of the warning box but the site is not uploading the image for some reason!!!

All Replies (1)

Zenos
Zenos
more options

Maybe you have a lock file that needs to be deleted.

http://kb.mozillazine.org/Profile_in_use