You have promoted your server to a DC, but find that when you go into server manager the alert prompting to promote the server to a DC is still there.

This seems to be a bug and there is an easy way to get around this:

1. Click Server Manager
2. Click the link to promote server to DC
3. Wait for the process to timeout, until you receive the error below. Click show more so the error pops up in a small window.

   Error determining whether the target server is already a domain controller. The target server is already a domain controller

4. Click the OK button
5. Click cancel button, so no windows are now showing
6. Close server manager
7. Open server manager and the alert should have disappeared