I think not… Why? Just do it. Maybe it corrects your problem with notes too.
I have no trouble with notes into MS Outlook, Outlook Express or Thunderbird. Maybe I’m lucky ;D
There is a special feature to add notes called UseAlternateRtfSyncing that is described here here on section [MailScanner].
This would seem an extreme solution to me uninstalling until Tech Support find a resolution (how would you know) for what is a minor problem of not seeing a clean note in an email and lose all the other AV protection that avast! offers.
I don’t bother with clean notes in inbound messages, the avast alarm will get your attention if there is a problem. Whilst I do have insert clean notes into outbound email.
It is no big deal for a virus to have its own clean message in the body of an email to try and deceive you, so you open that attractive attachment, so I don’t take anything like that at face value anyway.
To me those things lessen the importance of the insertion of clean note into an email anyway.
Don’t forget that you will not see the inserted note in the ‘Sent Items’ folder of your mail program,
because avast adds the note after the mail leaves the mail program. 