In short: open Settings > System > Activation, click Change next to “Change product key”, enter the 25 characters of your key and confirm. With an internet connection, activation takes less than a minute. If an error appears, its code almost always tells you the cause.
Before you start
- The edition must match the key. A Windows 11 Pro key activates Windows 11 Pro, a Home key activates Windows 11 Home. A Pro key entered on Windows 11 Home starts an upgrade to Pro (see below).
- An internet connection is needed during activation.
- The key format: 25 characters in 5 groups, such as XXXXX-XXXXX-XXXXX-XXXXX-XXXXX. The hyphens are added automatically.
Method 1: from Settings
- Press Windows + I to open Settings.
- Go to System > Activation.
- Expand “Change product key” and click Change.
- Enter the key, then click Next and Activate.
- The activation state should show “Active”.
Method 2: from the command line
Handy for volume licences (MAK) or for activating several PCs in a row. Right-click the Start button, choose Terminal (Admin), then type:
slmgr /ipk XXXXX-XXXXX-XXXXX-XXXXX-XXXXX
slmgr /atoThe first command installs the key, the second starts activation. To check the result, type slmgr /xpr: a window confirms that the machine is permanently activated.
Upgrade from Windows 11 Home to Pro without reinstalling
Enter a Windows 11 Pro key in System > Activation > Change product key. Windows adds the Pro features and restarts; your files and programs stay in place. Allow 5 to 15 minutes. To find out whether Pro will be useful to you, read our comparison Windows 11 Home or Pro.
The most common activation errors
| Code | What it means | What to do |
|---|---|---|
| 0xC004F050 | Key not valid for this edition | Check what you typed (O and 0, B and 8) and that the installed edition matches the key. |
| 0x803F7001 | No valid licence on this PC | The PC has never been activated: enter your key using method 1. |
| 0xC004C008 | Key already used the maximum number of times | Common with an OEM key already activated on another PC: contact the seller. |
| 0xC004F213 | No product key found on the device | Often after a motherboard change: enter the key again or run the troubleshooter. |
As long as Windows isn't activated, the System > Activation > Troubleshoot button automatically fixes several of these situations.
OEM or Retail: what changes if you change hardware
An OEM licence stays tied to the first PC it activates: replacing the drive, memory or graphics card changes nothing, but a new motherboard requires a new key. A Retail licence can be reactivated on another computer, one at a time. The details are in our guide OEM, Retail or volume licence.
Frequently asked questions
Do I need to reinstall Windows to enter a new key?
No. You can change the key at any time in Settings > System > Activation, without reinstalling or losing files.
Can a Windows 10 key activate Windows 11?
Generally, yes: a Windows 10 Pro key also activates Windows 11 Pro on a compatible PC, and a Windows 10 Home key activates Windows 11 Home.
What happens if Windows 11 isn't activated?
Windows works and receives updates, but a watermark is displayed and personalisation (wallpaper, colours, themes) is locked.
How long does activation take?
A few seconds with an internet connection. If Microsoft's servers don't respond, try again a little later: Windows remains usable in the meantime.
Need a key? Our Windows 11 and Windows 10 licences are delivered by email within minutes, with the official Microsoft download link and an invoice.