Hotmail/outlook.com/live.com and gmail accounts automatically copy sent mail to Sent, so uncheck 'Place a copy in' in the Copies & Folders section in Account Settings.

Thanks for the tip. Actually Gmail has that checked and it still only puts one copy in the sent folder but for some reason Hotmail is the "special one" and does it twice. What is weird is that I don't recall having to do this with TB68 and it didn't copy it in there twice. I wonder if something changed with it?

Anyway thanks again for the tip on how to prevent it with Hotmail.

The necessity to uncheck the option for Hotmail/gmail predates TB 68. Unless either of those services has changed policies, I can only guess that possibly some security app that scans outgoing mail interferes with the expected behaviour.

That is odd as my Gmail account is checked and it only gets the message once. My Hotmail one was getting it twice before updating to TB 78. Maybe it was unchecked in TB 68??? and got checked in 78???? Weird!

Anyway I'm just glad that you told me how to fix it. Thanks