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Upgraded to El Capitan OS X and now T-bird will not launch. Message: A copy of Thunderbird is already open. Only one copy of Thunderbird can be open at a time."

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  • Last reply by christ1

Jman88
Jman88
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Yesterday I upgraded from Moutain Lion to El Capitan on my MacBook.

Previously Thunderbird worked fine. Now it will not launch and I get an error message that "A copy of Thunderbird is already open. Only one copy of Thunderbird can be open at a time." Unfortunately there is no other copies of Thunderbird running. If I look in the "Force Quit" window I don't see Thunderbird.

I tried deleting and re-installing Thunderbird with latest version. I still get the same message.

Firefox works fine. Can anyone help? Thanks!

Yesterday I upgraded from Moutain Lion to El Capitan on my MacBook. Previously Thunderbird worked fine. Now it will not launch and I get an error message that "A copy of Thunderbird is already open. Only one copy of Thunderbird can be open at a time." Unfortunately there is no other copies of Thunderbird running. If I look in the "Force Quit" window I don't see Thunderbird. I tried deleting and re-installing Thunderbird with latest version. I still get the same message. Firefox works fine. Can anyone help? Thanks!

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christ1
christ1
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