I run with admin rights on my Windows 10 machine because it's the default and it's a pain in the neck to run without. "Sorry you don't have permissions to set the clock".
Have you also turned off UAC prompts? Because when I set the time it prompts me for the admin password and it works fine. I don't ever see the message that I don't have permissions to set the clock; I just see the icon on the button to set the time which shows that it will perform an elevation (prompt for password) to run it.
That was an exaggeration for emphasis. I could be more specific.. On a work laptop, I can write to my 'c:\Users\\Documents' folder, but if I try to access it via the various shortcuts on the left of the file manager, I am denied access. No UAC, even though I have the password for that. The permissions on the thing vary based on the path you access it by? That's messed up.