Think I've seen this before but may be wrong, don;t think it; specifically to do with Outlook.
Think it's caused by eDrawings trying to send a performance email.
eDrawings is used by PDM to show things in the preview tab for the file.
If you load up eDrawings and go to Tools>Options
Untick "Enable Performance Email"
That does seem to be the issue.
Well eDrawings and go to Tools>Options Untick "Enable Performance Email" is the solution.
But how to stop that tick from coming back on again periodically?
What is it with settings not sticking in Dessault software? there are a few random ones in SW that from time to time dont stick!