Fixing An Identical SID While Joining An Active Directory Domain

When you are setting up a new Active Directory forest and are trying to add a client to a domain, the following error may come up:

"The domain join cannot be completed because the SID of the domain you attempted to join was identical to the SID of this machine."

This error indicates that the Security Identifier (SID) of the domain controller is identical to the client machine's SID. A common cause of this issue is using a restored snapshot or a cloned machine without properly regenerating the SID. This guide explains the steps for fixing an identical SID while joining an Active Directory domain, ensuring a smooth and error-free domain join process.

1. Reset the Windows SID

Note: Vultr is not responsible for data loss or other unexpected updates to the system. Make a backup of the system before performing this action!

We will need to generate a new SID by resetting the current one on the client computer. We can do this by using the sysprep tool, which will reset some elements of your system.

Sysprep is located in C:\Windows\System32\Sysprep\sysprep.exe.

1. Double-click the .exe file to launch sysprep.

2. Change the System Cleanup Action to Enter System Out-of-Box Experience (OOBE)

3. Select Generalize.

4. Set Shutdown Options to Reboot.

   

5. Click "OK".

Step 2: Installation

Please wait while the system is generating its new SID. Check the online console regularly, as you will have to walk through the installation process. When the process is complete, please try joining the domain again.

Resources

See the Microsoft Sysprep documentation for more information.