Error Code Portal
MicrosoftWindows Win32Error code

623

ERROR_ILLEGAL_DLL_RELOCATION

Alternative forms: 0x0000026F · 0x26F · ERROR_ILLEGAL_DLL_RELOCATION · 0x8007026F

What does this code mean?

Code 623 · An issue reported by Windows Win32.

Official explanation · Original text

{Illegal System DLL Relocation} The system DLL %hs was relocated in memory. The application will not run properly. The relocation occurred because the DLL %hs occupied an address range reserved for Windows system DLLs. The vendor supplying the DLL should be contacted for a new DLL.

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 (500-999) (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