I noticed that I could not find certain items in my Sent Items folder the other day. I discovered that Outlook 2019 / Options / Mail / Save Message / 'Save copies of messages in the Sent Items folder' was unticked. So of course I re-ticked that option and it worked. Then I noticed this option becomes unticked every other time you launch Outlook. Then I finally noticed that there are about 20+ options that actually become unticked as well when this happens (not sending mail immediately when clicking send, not marking mail as read when highlighted, etc). But every other time I open a profile, the options are mysterious ticked again.
have 3 Outlook profiles and they all seem to be doing this.
did a full repair of Office 2019.
deleted and recreated 1 profile.
-Outlook 2019 connects to Exchange 2019 On Prem.am running Windows 10 2004 and Office 2019 has no more updates available (16.0.13328.20334).