Error Code Portal
MicrosoftWindows Win32Error code

8644

ERROR_DOMAIN_SID_SAME_AS_LOCAL_WORKSTATION

Alternative forms: 0x000021C4 · 0x21C4 · ERROR_DOMAIN_SID_SAME_AS_LOCAL_WORKSTATION · 0x800721C4

What does this code mean?

Code 8644 · An issue reported by Windows Win32.

Official explanation · Original text

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 is a symptom of an improperly cloned operating system install. You should run sysprep on this machine in order to generate a new machine SID. Please see <https://go.microsoft.com/fwlink/p/?linkid=168895> for more information.

Troubleshooting and diagnostic links

First check that the document's product, version, and environment match your situation.

Source and terms of use

System Error Codes (8200-8999) (WinError.h) ↗

Creator: Microsoft and MicrosoftDocs contributors
License: Creative Commons Attribution 4.0 International
Checked on: 2026-11-12

Modifications: Extracted numeric codes, symbolic names and English message text; converted Markdown/HTML to plain text and normalized whitespace; added Korean product context, namespace labels, status classification and separately labeled official links. No machine translation of message text.

Source details · Original licenses and notices