Error Code Portal
MicrosoftWindows Win32Error code

8645

ERROR_DS_UNDELETE_SAM_VALIDATION_FAILED

Alternative forms: 0x000021C5 · 0x21C5 · ERROR_DS_UNDELETE_SAM_VALIDATION_FAILED · 0x800721C5

What does this code mean?

Code 8645 · An issue reported by Windows Win32.

Official explanation · Original text

The undelete operation failed because the Sam Account Name or Additional Sam Account Name of the object being undeleted conflicts with an existing live object.

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