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Running Adprep

Before you can replace your old computer with a new computer that is running a new version of Windows Server, you need to first prepare the Active Directory schema by running adprep.

The adprep console utility will upgrade the Active Directory schema to add new object types required by the new operating system.

Windows Server 2025: If you are upgrading to Windows Server 2025, U-Move will prompt you to run adprep if needed. See below.

Windows Server 2012-2022: Windows will automatically run adprep during the promotion of the new domain controller.

How To Run Adprep

You need to run adprep on the domain controller that owns the Schema Master FSMO role. This is typically the root DC for the entire AD forest.

Prerequisites for Adprep

Before you run adprep, make sure that your user account is a member of the following groups:

• Enterprise Admins
• Schema Admins

Run dsa.msc and go to Users to add the groups to your user account. You will need to log off and log on again.

Prepare the AD Forest and Domain

Use the copy of ADPREP.EXE that is located on the installation media for the new operating system.

1. Apply the schema update to the Active Directory. On the old domain controller (DC) that owns the Schema Master FSMO role, insert the installation media for the new operating system and type the following:
   

   D:
cd \support\adprep
adprep /forestprep

   For D: substitute the disk letter of your installation media.
    
   If you are unsure which DC hosts the Schema Master role, you can view the FSMO roles by typing the command netdom query fsmo.
    
   This will apply the schema update to the AD forest.
    
2. Apply the domain update. On the old domain controller (DC) that owns the Infrastructure Master FSMO role, insert installation media for the new operating system and type the following:
   

   D:
\support\adprep
adprep /domainprep /gpprep

   For D: substitute the disk letter of your installation media.
    
   This will apply the AD security and group-policy updates to the domain.

Manually running adprep to upgrade to Windows Server 2012-2022

On the Windows Server installation media, you can find adprep at D:\Support\adprep\adprep.exe.

Running adprep is optional before upgrading to Windows Server 2012-2022. This is because Windows Server will run adprep automatically for you as part of the domain controller promotion process. This is called transparent adprep.

More Information

For detailed information on using adprep see Running Adprep.exe and the Microsoft command reference for adprep (Microsoft Learn).

You only need to run adprep once. It is not harmful if you run adprep multiple times or run it on the wrong DC. It will display an error message and quit without changing anything.

Warning Message: Need to run adprep

If you have not yet successfully run adprep, U-Move will display a warning message and refuse to proceed.

How to override this warning