Microsoft’s October 2025 Patches Disrupt Active Directory Sync on Server 2025 Systems

Microsoft has identified a critical issue affecting Windows Server 2025 systems following the installation of October 2025 security updates.

Directory Sync Failures Impact Large Organizations

This problem disrupts Active Directory directory synchronization, particularly impacting organizations managing large security groups with over 10,000 members. The issue affects applications relying on the Active Directory DirSync control for on-premises Active Directory Domain Services.

Organizations utilizing Microsoft Entra Connect Sync to integrate on-premises directories with cloud services are especially vulnerable. When synchronizing large Active Directory security groups exceeding 10,000 members, the process may return incomplete results, potentially leaving critical user accounts and permissions unsynchronized.

Microsoft officially acknowledged the issue on Sat, Oct 14, 2025, noting it first appeared after the September 2025 Windows security update, KB5065426. Subsequent updates in October continue to exhibit the same behavior, limiting administrators' options for maintaining operations.

As Microsoft investigates a permanent solution, affected organizations can implement a temporary workaround by modifying the Windows registry. This involves disabling a specific feature change responsible for the failures. Administrators must create a new DWORD value named 2362988687 with a value of 0 under the FeatureManagement Overrides section at HKEY_LOCAL_MACHINE.

Microsoft has issued a warning regarding this registry modification approach, emphasizing that incorrect changes can cause serious problems requiring operating system reinstallation. Only experienced administrators familiar with Windows registry operations should attempt this workaround.

Organizations uncomfortable with registry modifications may need to await an official patch. Microsoft has not provided a specific timeline for releasing a permanent fix but stated it will deliver a resolution in a future Windows update. This leaves enterprise administrators in a challenging position, balancing critical security updates and reliable directory synchronization.

This issue exclusively affects Windows Server 2025 installations, with no reports of similar problems on client versions of Windows or earlier server editions. Organizations using Windows Server 2022 or older versions remain unaffected by this synchronization failure.

System administrators managing large Active Directory environments should carefully evaluate their synchronization requirements before deploying the October 2025 updates to production domain controllers. Those who have already experienced synchronization failures can apply the registry workaround while monitoring Microsoft's official channels for updates on a permanent resolution.

Based on reporting by GBHackers.