HI kennethpatterson-4715,
Thanks for your reply.
1."I can run Outlook in admin mode, change the Programmatic Access option not to prompt and this works for a while until something unknown (maybe windows updates) happens then the settings go back to prompting."
Do you recall when you change "the Programmatic Access option not to prompt"?
Then we can enter below command to check which update patches (office update/skype/lync etc) installed recently then check if there is any office related update listed in "installed updates" in control panel like below picture.
get-hotfix
2.Do your end user set automatically forward outlook email to their personal email or third-party email?
3.Windows Security Center is not supported on server operating system versions, so I think setting "never warn me about suspicious activity" solution, meanwhile you can't set it for standard users (none administrators) and you can set it for administrators ( both local admin and domain admin), Is it true?
Could you share the method about how did you set "never warn me about suspicious activity" for each domain user? by using logon script or domain administrative Template policy?
Antivirus status shown as Unavailable (This version of Windows does not support antivirus detection)
https://learn.microsoft.com/en-us/outlook/troubleshoot/security/outlook-trust-center-shows-antivirus-status-as-unavailable
4.Is there office 2010 related software installed on problematical w2019 server?
5.Are you using the latest office or outlook administrative Template files (ADM/ADMX/ADML), then apply these policies for your problematical outlook?
Administrative Template files (ADMX/ADML) and Office Customization Tool for Microsoft 365 Apps for enterprise, Office 2019, and Office 2016
https://www.microsoft.com/en-us/download/details.aspx?id=49030
6.If we create a local standard test user on problematical w2019 RDS server then logon this local none admin user, is there 14.0 or 16.0 office key for this local none admin user?
(1)HKEY_CURRENT_USER\Software\Policies\Microsoft\Office\14.0
(2)HKEY_CURRENT_USER\Software\Policies\Microsoft\Office\16.0
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