Symptoms

When you scan a Microsoft DNS server, you see the following error


Error executing PowerShell command 'Get-DnsServerRootHintDetails'. No root hint found by a.root-servers.net. name server on servername server.


Cause

This can occur when the root hints data is corrupt on an Active Directory integrated Microsoft DNS server which is stored by default in the following location:


DC=RootDNSServers,CN=MicrosoftDNS,DC=DomainDnsZones,DC=domain,DC=int



If the Microsoft DNS server is not Active Directory integrated there may be an error in the cache.dns file which is by default found in the following location: 


C:\Windows\System32\dns\cache.dns"



Resolution

Review the "Root Hints" section of the Microsoft DNS server Manager MMC and check for any "Unknown" values and correct as necessary.




Workaround

Set the "Root Hints" optional component to "Scan (continue on failure)".