Don't open the attachment. Seriously as the file must be created to open. It certainly does not exist within the email, only a name and Mime encoded text exists in the email.

I receive several attachment, I understand that there is no other way if you do not receive the attachement.

The problem is that when you open the email and so the attachment, a copy of file is remaining in the temporary area. This is not correct.

Correct would be to remove the file after closed and did not keep history file of attached email.

True, but usually the temp file remains because Thunderbird is unable to delete it because the anti virus has it locked for scanning. That is why Windows has a disk cleanup utility and has done so since the at least XP. Windows should clean house there on each restart as many programs leave temp files behind for various reasons, it does not So run the cleanup utility regularly.