Troubleshooting Active Directory related issues as below:
Active Directory Replication, DCPromo and the installation of Domain Controllers, Active Directory Backup, Restore, or Disaster Recovery, Active Directory database issues and Domain Controller boot failures, Domain join issues, User, Computer, Group, and Object management, Group Policy, Account lockouts, Domain and forest trusts, Kerberos authentication, Permissions, access control, and auditing, Secure channel issues, Folder redirection, Offline files (client-side caching), Slow logon, Access to file shares (DFS namespace), File Replication Technologies (FRS and DFSR), Configuring and using Windows Backup or other recovery, Remote Desktop Services and Terminal Services, Virtualization and Hyper-V, Windows Desktop, User Logon, and User Profiles, Time Synchronization / Skew & maintenance, Troubleshooting Windows Terminal Servers & managing Terminal Services Licensing, etc.