Windows cann't verify that user name is unique

Hi All,

While create a user in another domain tree of same forest. I came accross the following warning message.

Although the server is DC and GC as well the reason for this error is due to that name resolution to forest root dc or other dc was failing due to which the this warning is generate although user will be create it won't be able to logon using other DC.

In order to resolve this you can either create conditional forwards or stub zone to parent root or other domains which have gc present.  You need to keep this in mind when you create stub zone and save it to all dns servers in Active Directory domain x (your domain) then it has be done using Enterprise Admin Account otherwise DNS Application partition will not be created alternatively if you are only using AD intergrated DNS you can save this on all DC in active directory domain x.