Microsoft has effectively shut down one of the most widely used illicit activation methods for Windows—KMS38. Users report that the offline mechanism no longer functions on Windows 10 and Windows 11, despite the absence of explicit notes in recent release documentation. This outcome caps years of incremental hardening aimed at informal tools from the Massgrave (MAS) project and similar activators.
What KMS38 Was and Why It Expired in 2038
KMS38 was a community technique that stretched the standard Key Management Service (KMS) activation period from 180 days to 19 January 2038. It leveraged the Windows utility GatherOSstate.exe, originally intended to assess upgrade eligibility, to anchor an extended activation state. The year-limit aligned with the well-known Year 2038 (Y2K38) constraint—an integer overflow in 32-bit time representations that caps certain timestamps at 2038. See background on the Year 2038 problem for context.
How Microsoft Closed the KMS38 Loophole
Early signals: GatherOSstate removal in preview builds
In early 2024, signs of enforcement emerged when build Windows 26040 shipped without GatherOSstate.exe in installation media. As a result, major upgrades and clean installs reset the previously “extended” state, pushing users back to compliant activation channels and shrinking room for offline manipulation.
October–November 2025: final steps via Windows updates
An optional Windows 11 update, KB5067036 (October 2025), reportedly deprecated GatherOSstate functionality outright. Subsequent Patch Tuesday packages—KB5068861 and KB5067112 (November 2025)—completed the lockout, and KMS38 ceased working on supported configurations. While these changes were not highlighted in release notes, community testing indicates the method is effectively blocked.
Massgrave’s Response and Current Tooling Landscape
The Massgrave team acknowledged the breakage and removed KMS38 support in MAS 3.8. Community discussions reference HWID and TSforge as alternatives; however, these remain unauthorized activation tools and carry both legal and cybersecurity risks. Organizations should avoid any non-official activators.
Security, Legal, and Operational Risks of Illicit Activation
Illegitimate activators are frequently flagged by enterprise defenses as HackTool or Riskware, not solely for policy reasons but because they modify licensing components and can introduce persistent risks. Microsoft Defender, for instance, uses families like HackTool:Win32/AutoKMS to classify such utilities. Distribution through forks and repackaged binaries increases the probability of malware, rootkits, or backdoors, complicating digital hygiene and incident response.
Beyond security, license compliance is a material concern. Unlawful activation exposes organizations to audit findings, penalties, and reputational damage. From an operational standpoint, Microsoft’s removal of GatherOSstate paths moves activation toward stricter online validation, reducing the attack surface for offline tampering. For official models—including Volume Licensing, KMS, and Active Directory-based Activation (ADBA)—refer to Microsoft Learn: Volume Activation.
Practical Guidance for Enterprises and IT Teams
Start with a license inventory and validation across all Windows endpoints. Remove legacy activators and verify systems for detection artifacts (e.g., Defender signatures related to AutoKMS). Where feasible, reimage or re-enroll affected machines to reset trust and eliminate residual modifications.
Standardize on supported activation channels: digital licenses, Microsoft KMS, or ADBA. Restrict execution of unsigned scripts and untrusted binaries via AppLocker or Windows Defender Application Control. Monitor for activation anomalies in EDR logs, and align software asset management processes with your Volume Licensing entitlements to withstand compliance audits.
Finally, validate Windows update rings and test critical KBs before broad deployment. With KMS38 no longer viable, any endpoints relying on it may revert to a non-activated state after updates, affecting user experience and support queues.
Microsoft’s quiet deprecation of KMS38 underscores a broader trend: closing activation bypasses and reinforcing integrity checks. The most resilient path forward is to remove unauthorized tools, adopt supported activation mechanisms, and strengthen governance around software licensing. Proactive remediation now reduces breach risk, audit exposure, and operational friction later—while ensuring Windows activation remains secure, compliant, and manageable at scale.
