I suffered this problem since I have more than one googlemail accounts defined in TB. When I am in one googlemail account, I compose a new mail, after sent, I found that it is sent from the other account. There is already a question and answer archived with the same question; and I am writing this to give a more targeted answer. It could be because you have set the SMTP servers improperly to each account. There are separate outgoing server (smtp) accounts defined for each gmail addresses as mentioned in the archived reply. However it is not about which is default; but it is about redundant selection of the outgoing server (smtp) accounts. Pay attention to choose a separate outgoing server (smtp) account for each gmail address. This would resolve the issue, probably. Regards. Umut