We are running Active Directory and DNS Server on the Same Windows Server 2008 R2 as Virtual Machine on vSphere 5 Platform. Since it is for College environment every month we have to delete or create 1000 users. Recently iSCSI based Storage which is used to store the Virtual Machines (Includes Active Directory VM also) is corrupted. Then we have restored the Active Directory Server from the Clone image (of Active Directory) which was taken in Dec 2012. Here Some client machines are authenticating to the Active Directory but still some client machines are authenticating through ADC. But ADC unable to sync from PDC. What can do now in order to sync ADC from PDC. I executed dcdiag on the ADC also.