SPSE - User Profiles Synchronization Service Application creation issue

sonisp The difficulty you're facing in creating the User Profiles Synchronization Service Application in SharePoint Server 2016 appears to stem from a potential conflict with the previously installed KB5002506 patch. This particular patch has introduced a change that requires manual intervention to ensure the UPS Proxy is created correctly.

Firstly, check for the existence of an already running UPS Proxy in your SPSE environment. You can do this by inspecting the services in the Services console or using the provided PowerShell command. If a UPS Proxy is found to be already running, proceed to step 5. Next, stop the UPS service to prevent any interference during the creation of the UPS Proxy. Utilize the provided PowerShell command for this task.

Following that, remove the UPS Proxy from the registry by deleting the relevant registry key. The provided PowerShell command facilitates this action. Restart the UPS service to allow the system to create a new UPS Proxy. Use the provided PowerShell command for this purpose.

Now attempt to create the UPS service application again. The process should proceed without encountering errors, and the UPS Proxy should be successfully generated. Verify the UPS Proxy's status to ensure it is running correctly. This can be confirmed by checking the services in the Services console or employing the provided PowerShell command. If the UPS Proxy is confirmed to be operational and the UPS service application is functioning as expected, the issue should be resolved, and the UPS service should be able to synchronize user profiles effectively.