Activate Windows 11 with a product key
Open Settings › System › Activation, click “Change product key” and enter the 25 characters of your key. Windows checks the key online and activates within seconds. An Internet connection is required; on Windows 11 Home, a Pro key triggers the upgrade after a restart.
1. Check the installed edition
A Windows 11 Pro key activates the Pro edition, a Home key activates the Home edition. Open Settings › System › Activation (shortcut Windows + I): the edition and activation status are shown there.
2. Install Windows 11 if needed
On a blank PC, download the media creation tool from the official Microsoft website and prepare a USB stick of at least 8 GB. The PC must have a TPM 2.0 chip and UEFI Secure Boot.
3. Enter the product key
Open Settings
Windows + I, then System › Activation.
Change the product key
Click “Change” on the “Change product key” line.
Enter the 25 characters
Copy them from the delivery email, then confirm.
Check
The page says “Windows is activated”. On Home, restart to complete the upgrade.
4. Activate from the command line
If the interface does not respond, open Terminal as administrator and run these two commands, replacing the Xs with your key:
slmgr /ipk XXXXX-XXXXX-XXXXX-XXXXX-XXXXX slmgr /ato
5. Common error codes
| Code | Meaning | What to do |
|---|---|---|
| 0xC004F050 | Key not valid for the installed edition | Check the edition (Home or Pro) and what you typed. |
| 0xC004C003 | Key rejected by the activation server | Reply to the delivery email: we will replace the key. |
| 0x803F7001 | No valid licence found on this PC | Enter your key via “Change product key”. |