DNS, AD and Windows Register

Some time ago we have a failure of AD. We had to install it from the scratch. So I ran dcpromo, marked that this is the last DC in the network. Restart and I had installed new AD. But is it working as it should be?

The company I work for owns several hotels, One of them, I wont mention its name, not longer exists. Building was renovated and now new hotel is in this place.

From some time in the Event Viewer I get the DNS entries that DNS service can not open_msdc.some_zone.local zone. I realized that the name of this ‘missing’ zone is the name of the hotel I mention above. But why, and how? I have removed the AD with the DNS so even if it existed before, the zone should be gone for good now, right? Wrong!

DNS zone information is stored in the Windows system registry and after uninstalling the DNS and AD, this information is still there (sick!).

The solution was to remove the keys from the branches of HLMSoftwareMicrosoftWindows NTCurrent VersionDNS ServerZones appropriate for non-existent zone.