How to activate Windows 11 with a product key
By the MasterKeys support team · Last reviewed
Short answer: Open Settings › System › Activation › Change product key, enter your 25-character key, and click Activate. On a new install, you can enter it during setup instead, or skip and add it later.
Activate an installed copy
- Open Settings (Win + I) › System › Activation.
- Next to Change product key, click Change.
- Type the 25-character key (XXXXX-XXXXX-XXXXX-XXXXX-XXXXX) and click Next › Activate.
- The status changes to Windows is activated with a digital license. Sign in with a Microsoft account to link it, which makes moving to a new PC easier.
Activate during a clean install
- Create a USB installer with Microsoft's Media Creation Tool (microsoft.com/software-download/windows11).
- Boot from the USB, choose language and keyboard, and enter the key when asked. Setup installs the matching edition (Home or Pro).
Common errors
| Error | What it means | Fix |
|---|---|---|
| 0xC004F050 | Key doesn't match the installed edition | A Pro key on Home: use Settings › Activation › Change product key, and Windows upgrades to Pro. |
| 0x803F7001 | No valid license found after hardware change | Run the Activation troubleshooter and choose "I changed hardware on this device recently". |
| 0xC004C008 | Key already used on another PC | Deactivate the old PC, or contact support for a replacement. |
Still stuck? Send us your order number and a screenshot, and we'll sort it out.
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