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Thunderbird sending duplicate emails

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I just installed Thunderbird on my new win 10 machine. I use pop3 and my gmail account. I also transferred my address books and local folders. It worked fine on my old win 10 pc with the same exact settings, but is now delivering duplicate, sometimes triplicate, emails to recipients. Only *one* sent copy is saved on my end - it's the people I'm sending messages to that are getting multiples of the same message. Anyone have any idea how to fix it?

I just installed Thunderbird on my new win 10 machine. I use pop3 and my gmail account. I also transferred my address books and local folders. It worked fine on my old win 10 pc with the same exact settings, but is now delivering duplicate, sometimes triplicate, emails to recipients. Only *one* sent copy is saved on my end - it's the people I'm sending messages to that are getting multiples of the same message. Anyone have any idea how to fix it?

All Replies (2)

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Do you have an Anti-virus product on new computer ? If yes: Stop AV from scanning outgoing emails.

Or perform test which will rule out the AV: Start computer in 'Safe Mode with networking' Start Thunderbird. Send email as test. If email is sent correctly - only once - then it is possible you have AV product scanning the outgoing email and it is causing an interuption

Are you sending the emails using a list or are they individual one off emails to contacts?

Are you sending one email to two email addresses that belong to same recipient ? If yes: then the recipient may have an auto forwarding service and so sees both in one account.

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Thanks for the prompt reply. I appreciate all the tips and just got my first chance yesterday to delve into the problem a little more. I now think the issue might lie on the sender's end instead of mine. I don't use email that much and at the time I posted my question, had only sent messages to 1 person (single individual off of my contacts list). I've since sent message to multiple people (again - individually - not on a list) and all but 1 (the same one as before) says they received duplicates. I did, however, follow your advice and confirm my AV wasn't the source of the problem. It's not something I thought of. Thanks for your help- it was appreciated.