Or just turn off UAC.
If you’re getting a login failed for your Windows user – which you’re sure you put in the sysadmins role – it’s probably because UAC isn’t pasing all your group memberships to SSMS when you run it, and therefore giving you access denied. If you check your SQL errorlog and you see something like this:
Login failed for user Username Reason: Token-based server access validation failed with an infrastructure error. Check for previous errors.
It’s probably UAC. Try right clicking and running as administrator and seeing if it goes away. Of course if you added your user explicitly you’re probably fine, but just to get a cluster up and running I added my domain admins user to the DB – and of course that’s a membership that UAC will mask.
