Why is THunderbird sending duplicate emails to the same sender for each single email?
I'm using TB 38.7.2. Every time I send an email - the sent box shows 2 exact same messages sent. My receivers so far report getting two messages. Why is this happening and what is the fix. Using Windows 10 OS.
Ñemoĩporã poravopyre
At the top right of the Thunderbird window, click the menu button 
> Options > Account Settings > Copies & Folders.
Uncheck 'Place a copy in Sent Folder'.
Opaite Mbohovái (2)
Ñemoĩporã poravopyre
At the top right of the Thunderbird window, click the menu button > Options > Account Settings > Copies & Folders.
Uncheck 'Place a copy in Sent Folder'.
Your answer (in part) "Options > Account Settings > Copies & Folders. Uncheck 'Place a copy in Sent Folder'."
When I try to do this I get the following response with a "bong" : "An account with this name already exists. Please enter a different account name."
It does not allow me to make any changes.