Hello Jeff Perkins,
The root cause is a legacy Group Policy Object (GPO) leftover from the Small Business Server (SBS) environment. The "greyed out" behavior in Windows settings is the definitive indicator that a "Winning GPO" is overriding local administrator control. This is a configuration drift issue common in SBS-to-Standard migrations, specifically regarding the "Windows SBS Client" policy templates that persist aggressively.
To resolve this permanently, you must isolate the specific policy rather than applying broad strokes. Execute gpresult /h C:\Support\RDP_Report.html from an elevated command prompt on an affected Windows 11 client to generate a precise policy resultant set. Open the report and locate the winning GPO under Computer Details > Administrative Templates > Windows Components > Remote Desktop Services > Remote Desktop Session Host > Connections. The specific setting locking your UI is "Allow users to connect remotely by using Remote Desktop Services." You must edit the identified GPO in the Group Policy Management Console (GPMC) and change this setting to "Not Configured" to restore local control, or "Enabled" to force RDP on while keeping the UI greyed out.
Furthermore, Windows 11 strictly enforces Network Level Authentication (NLA) and Firewall profiles. In the same GPO path, verify that "Require user authentication for remote connections by using Network Level Authentication" is not conflicting with your client capabilities. You must also validate the "Windows Defender Firewall: Allow Inbound Remote Desktop exceptions" setting under Computer Configuration > Administrative Templates > Network > Network Connections > Windows Defender Firewall > Domain Profile. If this is not explicitly enabled with the correct scope (e.g., localsubnet), the RDP listener will be active but unreachable. Finally, if gpupdate /force does not resolve the issue, inspect HKLM\SOFTWARE\Policies\Microsoft\Windows NT\Terminal Services for a "tattooed" registry value named fDenyTSConnections; if it exists with a value of 1 without an active GPO enforcing it, delete the key manually.
Hope you found something useful in the answer. If it helped you get more insight into the issue, please consider accepting it. Thank you and have a nice day!
VP