Microsoft has identified that Windows updates from August 29, 2025, are causing authentication failures due to duplicate Security Identifiers (SIDs). These issues impact Windows 11 24H2, 25H2, and Windows Server 2025, disrupting remote connections and access to network resources. #SecurityIdentifiers #WindowsUpdates
Keypoints
- The updates enforce new security checks on SIDs, leading to authentication failures on systems with duplicate SIDs.
- Cloning or duplicating Windows installations without proper preparation can create duplicate SIDs and cause issues.
- Symptoms include failed login attempts, “access denied” errors, and specific error messages like SEC_E_NO_CREDENTIALS.
- Microsoft recommends rebuilding systems with duplicate SIDs and offers a Group Policy workaround after support consultation.
- Previous updates have also addressed related authentication issues, highlighting ongoing Windows security improvements.