duplicate SIDs Archives

Winsage

November 3, 2025

Microsoft Sounds Windows 11 And Server Update Failure Alarm

Microsoft has confirmed that users of Windows 11 and Windows Server are experiencing authentication failures due to updates released on or after August 29. This issue, detailed in Microsoft Support posting KB5070568, is linked to duplicate Security IDs (SIDs) on devices, affecting Windows 11 versions 24H2 and 25H2, as well as Windows Server 2025. The problem arises from new security protections that enforce checks on SIDs, which are necessary to maintain user account integrity and prevent unauthorized access. Duplicate SIDs typically result from unsupported cloning or duplication of a Windows installation without using the Sysprep tool. The recent update mandates SID uniqueness, blocking authentication handshakes between devices with duplicate SIDs. To resolve this, users must rebuild their devices using supported methods for cloning or duplicating a Windows installation to ensure unique SIDs.

Winsage

October 24, 2025

SID happens

Users who installed updates KB5064081 or KB5065426 on Windows 11 and Server 2025 may experience a bug related to duplicate Security Identifiers (SIDs) in cloned systems, leading to loss of user identities and compromised functionalities like network shares and remote desktop access. The only solution is a complete system rebuild. Users are advised to back up data, review cloning practices, and stay informed about Microsoft updates regarding this issue.

Winsage

October 24, 2025

Weird Authentication Failures? Could Be That Microsoft Doesn’t Like Duplicate SIDs Anymore

Microsoft has introduced a feature that requires unique Security Identifiers (SIDs) across systems, effective August 29, 2025, impacting users who previously cloned images with duplicate SIDs for Kerberos or NTLM connections. This change has led to SECENO_CREDENTIALS errors in the Event Viewer and other reported issues. Microsoft recommends using the Sysprep tool for fresh machine setups. A workaround exists through a Group Policy setting that allows duplicate SIDs, but users must contact Microsoft support to access it, as it is not available by default. This update marks the third occurrence of authentication errors associated with Microsoft updates.

Winsage

October 23, 2025

Microsoft says Windows update may have caused login problems

Microsoft has acknowledged that recent updates for Windows operating systems, specifically Windows 11 versions 24H2 and 25H2, and Windows Server 2025, may have caused login complications for some users. The problematic updates are KB5064081 (OS Build 26100.5074) released on August 29, 2025, and KB5065426 (OS Build 26100.6584) released on September 9, 2025. These updates can lead to authentication failures related to Kerberos and NTLM protocols, particularly on devices with duplicate Security IDs (SIDs). Symptoms include repeated prompts for credentials, failed access requests, inability to access shared network folders, challenges in establishing Remote Desktop connections, and specific error messages logged in the Event Viewer. The root cause is enhanced security measures that enforce checks on SIDs, which can block authentication handshakes when devices have duplicate SIDs, often due to unsupported cloning methods. There is no automated fix; administrators are advised to rebuild devices with duplicate SIDs using supported cloning methods or to configure a special Group Policy for a temporary workaround.