wrote:

Well, so far, this is what appears to work:

Completely deleting my account and identity, shut down Outlook, startup
again, make a new account with the same settings.

After doing this, I am back to one email displayed for each email
received. Which is nice.

Actually, this is not a complete solution.

Because every time I have a lot of email to pull from the server (like,
oh, I don't know, every single morning for instance) this problem comes
back.

Outlook will download some % of the emails to my inbox correctly, one
copy per mail, but somewhere towards the end of the list of mails it
will switch into 2 copy mode. And there is no way to get it out of this
mode that I know of, except to delete and recreate my account.
Sometimes it will download 80% or so of the ~100-120 mails I would get
on a typical morning correctly. Sometimes, like this morning, it
downloaded all except the last two correctly. But so far it is
completely predictable: download 100 mails or so, and it will switch
into 2 copy mode at the end.

Every single day.

I am a patient man, but seriously, this is ridiculous.