How to Migrate Active Directory from Windows Server 2008 to a Newer Server OS

You can migrate Active Directory (AD) from Windows Server 2008 to a newer Windows Server OS using a Domain Controller Upgrade and Transfer process. Microsoft provides a smooth transition path, but there are a few steps to follow carefully.

Step 1: Prepare Your Environment

1. Check Current AD Health on the 2008 Server
   • Run:

     dcdiag /v
     

   • Fix any errors before proceeding.
2. Check AD Functional Level
   • Open Active Directory Users and Computers (ADUC) (dsa.msc).
   • Right-click the domain > Raise Domain Functional Level.
   • Ensure it’s at Windows Server 2008 or higher (Required for migrating to newer versions).
3. Ensure You Have a New Server Ready
   • Install Windows Server 2016, 2019, or 2022 on a new machine.
   • Assign a static IP address in the same network as the old server.
   • Set Primary DNS to the Windows Server 2008 DC.

Step 2: Install AD DS on the New Server

1. Join the new server to the existing domain.
2. Open Server Manager on the new server.
3. Click Manage > Add Roles and Features.
4. Select Active Directory Domain Services (AD DS).
5. Follow the prompts and install.

Step 3: Promote the New Server as an Additional Domain Controller

1. Open Run (Win + R), type:

   dcpromo
   

   (If using Windows Server 2016/2019/2022, use Server Manager instead.)

2. Choose “Add a domain controller to an existing domain”.
3. Enter Domain Admin credentials.
4. Ensure Global Catalog (GC) and DNS are selected.
5. Complete the setup and restart the new server.

Step 4: Transfer FSMO (Flexible Single Master Operations) Roles

Your old server holds 5 FSMO roles that must be moved.

1. On the new server, open Command Prompt (Admin) and run:

   netdom query fsmo
   

   This shows which server holds the FSMO roles.

2. Transfer roles using PowerShell on the new server:

   Move-ADDirectoryServerOperationMasterRole -Identity "NewServerName" -OperationMasterRole 0,1,2,3,4
   

3. Verify the new server holds all roles:

   netdom query fsmo
   

Step 5: Decommission the Old Windows Server 2008 DC

1. On the old server, open Command Prompt and run:

   dcpromo
   

2. Follow the Uninstall AD DS Wizard.
3. Reboot the old server.
4. Remove the old DC from Active Directory Sites and Services (dssite.msc).

Step 6: Update Client Computers & DNS

1. Update DHCP and DNS settings to point to the new DC.
2. Run:

   ipconfig /flushdns
   ipconfig /registerdns
   gpupdate /force
   

3. Test logins and AD functionality.

Migration Completed!

• Your Active Directory is now on the new server.
• The old Windows Server 2008 is safely removed.
• You can now upgrade to future Windows Server versions more easily.