8644 is a directory service result. Microsoft’s system-code table describes this value as: “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.”
Code reference and safe checks
Read the exact screen and operation before selecting a repair. This page does not run commands or collect files, keys or logs.
What this value means
Microsoft’s system-code table describes this value as: “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.”
ERROR_DOMAIN_SID_SAME_AS_LOCAL_WORKSTATION is a Win32 system result, usually returned to an application or API caller. It is not a Windows blue-screen code or a diagnosis of the whole PC.
| Code | 8644 |
|---|---|
| Hex form | 0x21C4 |
| Symbol | ERROR_DOMAIN_SID_SAME_AS_LOCAL_WORKSTATION |
| Windows family | Win32 system codes |
| Source level | Microsoft code and symbol entry |
Safe next steps
- For 8644 (ERROR_DOMAIN_SID_SAME_AS_LOCAL_WORKSTATION), record the domain or directory operation, server, account type, and exact message. These codes usually need administrator context.
- Have the directory administrator check service reachability, replication or object state as indicated by the message and relevant logs.
- Avoid changing domain membership, access control, or directory objects on a managed device without an approved plan.
After one step, repeat the original operation and record whether this same code returns. A different code needs a fresh interpretation.
What this code cannot prove
The source establishes the identifier and reference meaning. It does not establish the cause on your specific PC.
Stop before changing security, licensing, directory or production settings on a managed device; involve the responsible administrator.
Official reference and verification
Source type: Microsoft code and symbol entry. Checked against the source set on Nov 2, 2026.
The reference gives the meaning of this identifier. It does not inspect your PC or guarantee that one repair will work.