How to Remove KMS Activation from Windows and Activate It the Right Way

To remove KMS activation, open Terminal as an administrator and run slmgr /upk, slmgr /cpky, and slmgr /ckms, then restart. That removes the KMS key and server setting. Windows will show as not activated until you add a genuine license.

If the KMS activation came from an “activator” tool rather than your employer, also remove the tool and scan for malware. These tools often bring unwanted software with them.

Is this a work or school PC? Companies use KMS legitimately to activate their computers. Don’t remove it from a managed device. Talk to your IT department instead.

What KMS activation is

KMS (Key Management Service) is how businesses with volume licenses activate many PCs at once from their own server. A PC using it has a generic KMS client key that has to check in with a KMS server regularly. A KMS client key is not a retail license, so it can’t activate a home PC on its own.

Unofficial activators fake a KMS server so Windows thinks it’s activated. That isn’t a valid license, and many of these tools are bundled with malware.

Step 1: Check whether your PC uses KMS

1. Right-click Start and select Terminal (Admin) or Windows PowerShell (Admin). Select Yes if asked.
2. Type slmgr /dli and press Enter.
3. Read the small window that appears. If the description includes VOLUME_KMSCLIENT, the PC is set up for KMS activation.
4. Optional: run slmgr /xpr to see when the current KMS activation expires.

Step 2: Remove the KMS key and server setting

In the same administrator window, run these one at a time. Wait for the confirmation box after each one and select OK.

1. slmgr /upk uninstalls the current product key.
2. slmgr /cpky clears the product key from the registry.
3. slmgr /ckms removes any KMS server name or address and restores the default setting.
4. Restart your PC.

After the restart, Settings > System > Activation will show that Windows isn’t activated. That’s expected.

Step 3: Remove the activator and scan for malware

Skip this step if the KMS setup came from a previous employer rather than a tool.

1. Open Settings > Apps > Installed apps. Uninstall anything related to the activator, such as programs with “KMS,” “activator,” or similar names.
2. Open Task Scheduler, select Task Scheduler Library, and delete any tasks the activator created to re-run itself.
3. Open Windows Security > Virus & threat protection > Scan options. Select Microsoft Defender Antivirus (offline scan), then Scan now. The PC restarts and scans before Windows loads.
4. After the scan, run a Full scan as well.

If you use another antivirus app (such as Malwarebytes or Norton), Windows Security shows that app on the Virus & threat protection page instead of the scan options. Run a full scan in that app. You can also expand Microsoft Defender Antivirus options there and turn on Periodic scanning for a second opinion.

If Windows Security finds threats it can’t remove, or you still see pop-ups or unknown programs afterward, consider backing up your files and doing a clean reinstall of Windows.

Step 4: Activate Windows with a genuine license

Which path you take depends on the license you have.

Your PC came with Windows or was upgraded for free

It likely has a digital license tied to its hardware.

1. Go to Settings > System > Activation.
2. Select Troubleshoot if it’s offered. Windows checks Microsoft’s servers for a license for this PC.
3. If activation succeeds, you’ll see Windows is activated with a digital license.

You have a product key

1. Go to Settings > System > Activation.
2. Under Upgrade your edition of Windows (or the product key section if Windows isn’t activated), select Change next to Change product key, then enter the 25-character key.

You don’t have a license

Select Open Store on the Activation page to buy one from the Microsoft Store, or buy from an authorized retailer. Avoid very cheap “keys” from marketplaces. They’re often resold volume keys that stop working.

The edition doesn’t match your license

Activators often switch Windows Home to Pro or Enterprise. If your PC’s license is for Home, it won’t activate Pro. You have two options: buy a Pro upgrade from the Activation page, or reinstall the edition you own from Microsoft’s official installation media.

For every legitimate activation option, including reactivating after a hardware change and common error codes, see how to activate Windows 11 or Windows 10.

Frequently asked questions

Will removing KMS activation delete my files?

No. The slmgr commands only change licensing. Your apps and files stay where they are.

What happens if I don’t activate Windows afterward?

Windows keeps working, but you’ll see an “Activate Windows” watermark and can’t change personalization settings until it’s activated.

Is KMS activation illegal?

KMS itself is a legitimate Microsoft service for businesses with volume licenses. Using an activator to fake it without a license isn’t a valid license and breaks Microsoft’s license terms.