Microsoft’s monthly Patch Tuesday often brings predictable security fixes, stability improvements, and occasional feature changes. But this month’s update introduced a quiet, undocumented change that caught many users off guard — especially those relying on unofficial activation tools.
Before diving into the details, let’s set the stage. The November 2025 Patch Tuesday included update KB5068861 for Windows 11 24H2 and 25H2, along with corresponding updates for Windows 10. On the surface, these patches appeared routine. However, behind the scenes, Microsoft shut down a long-standing loophole used for unauthorized activation of Windows.
This article explains exactly what happened, why Microsoft made this decision, what KMS38 was, and why using unofficial activation tools can put your system and network at risk.
Understanding the Context Behind the Block
Before exploring the actual change, it helps to understand the background. Over the past decade, Microsoft has made major efforts to reduce unauthorized activation methods. While the company has become more flexible about genuine licensing (for example, activation through digital licenses), it still actively patches loopholes used for piracy.
This month’s Patch Tuesday took a significant step by disabling one of the most widely used unauthorized activation tools.
Let’s move to the core of the issue.
What Exactly Did Microsoft Block?
Hidden inside the November 2025 security update was a silent change: Microsoft blocked the KMS38 activation method, which had been functioning for several years.
This change was not listed in the official changelog. It was simply implemented in the background — a common practice when security loopholes are involved.
What is KMS38?
KMS38 was an unofficial activation method distributed by the Massgrave project (MAS), short for Microsoft Activation Scripts. This tool was designed to activate Windows without an official license key.
Here’s what made KMS38 unique:
- It used a special loophole in the licensing system.
- It tricked Windows into extending activation all the way to January 2038.
- It bypassed the typical 180-day activation cycle used in legitimate Key Management Service (KMS) environments.
- It required no connection to Microsoft servers for renewal.
In simple terms:
KMS38 allowed users to activate Windows illegally for 13+ years.
With the latest update, this loophole has been permanently closed.
Confirmation From the Developers Behind MAS
The author of the Massgrave project confirmed the change publicly. According to their statement:
- KMS38 no longer works after installing the November 2025 patches.
- The loophole Microsoft used to ignore license checks has been closed.
- Users who attempt to activate through the old method will now fail.
This means that anyone currently attempting to use MAS tools must transition to legal activation methods moving forward.
Why Microsoft Likely Made This Move
Before jumping into the risks of piracy, it’s important to recognize why Microsoft continues to target unofficial activation tools:
- Security Threats
Unauthorized activation often involves modifying system files, injecting scripts, or bypassing security layers — all of which can weaken your system’s integrity. - Enterprise Risk
Corporate networks are especially vulnerable. A single compromised, pirated copy of Windows can expose the network to malware or unauthorized access. - Software Compliance
Many organizations must adhere to licensing regulations. Tools like KMS38 undermine these requirements. - Malware Distribution
Pirated activators are a common method for spreading malware and backdoors. Some versions even include data-stealing scripts.
From Microsoft’s perspective, closing KMS38 was a necessary move to protect users and networks.
Why You Should Avoid Pirated Windows Activators
Let’s briefly address this point — not from a moral standpoint, but from a technical and security perspective.
When you use unofficial activation tools:
- You may disable Windows security components without realizing it.
- You risk running activation scripts that include hidden malware, spyware, or rootkits.
- System updates may break, leaving your device vulnerable to exploits.
- Enterprise networks can be exposed to large-scale attacks.
- Many pirated activators modify core system files, introducing long-term instability.
For these reasons, even tech-savvy users should avoid such methods. A genuine activation method — digital license, OEM key, retail key, or organization-managed activation — ensures long-term stability and security.
What Happens Now for Users Relying on KMS38?
Now that the method has been blocked:
- Systems already “activated” with KMS38 may revert to unlicensed status after major updates or repeated license checks.
- New activations using this method will fail immediately.
- MAS tools will likely move to alternative scripts — but those may also be patched eventually.
The recommended and safe approach is to activate Windows through official Microsoft-supported methods, such as:
- Genuine OEM product keys
- Retail digital licenses
- Microsoft Store purchases
- Official enterprise KMS/MAK systems
- Digital license linked to a Microsoft account
Microsoft’s activation troubleshooting page:
https://support.microsoft.com/windows/activation
Frequently Asked Questions (Q&A)
1. Will my system stop working if it was already activated using KMS38?
Your system won’t stop working, but activation may fail after future updates or validation checks. You may also see “Windows not activated” messages over time.
2. Can the old KMS38 loophole be reactivated?
No. This is a server-side and client-side block. Re-enabling it would require bypassing updated licensing services — which poses major security risks.
3. Are there any legal free ways to use Windows?
Yes. You can install Windows 10/11 without activation and use most features indefinitely. Only personalization settings (wallpaper, themes) are restricted.
4. Can I stay on an older build to keep KMS38 working?
Technically yes, but it’s strongly discouraged. Older builds miss critical security patches and leave your PC vulnerable.
5. Does this affect Office activators too?
This specific block is for Windows activation (KMS38). Office activators may be affected separately depending on future updates.
Final Thoughts
Microsoft’s decision to quietly disable the KMS38 activation method marks an important step toward reducing piracy and improving system security. While many users relied on this workaround, the truth is that unauthorized activation exposes your system — and any connected network — to real risks.
As Windows continues to evolve, it’s best to stick with legitimate activation methods that ensure long-term updates, security, and stability.
If you rely on Windows daily for work or personal use, staying on a genuine, fully supported version is always the safer route.
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