This rule is used to collect events that are related to naming collisions for the AD Duplicate Accounts report.
When a collision of this type occurs, multiple accounts share the same name. It is then impossible for the Active Directory® directory service to distinguish which of the accounts the name refers to.
Attempt to update DnsHostName and HOST Service Principal Name (SPN) attributes of the computer object in Active Directory failed because the Domain Controller '%1' had more than one account with the name '%2' corresponding to this computer. Not having SPNs registered may result in authentication failures for this computer. Contact your domain administrator who may need to manually resolve the account name collision.
Manually change one of the account objects to a unique name.
For more information, see:
Microsoft Help and Support for Microsoft Windows Server 2003
Microsoft Knowledge Base