Key activation
How to activate Microsoft Windows and Office keys
Enter your Windows product key in Settings, or redeem your Office key at setup.office.com.
Windows and Office product keys are 25 characters long. The key must match the edition you have installed: a Windows 11 Pro key will not activate Windows 11 Home, for example.
Windows 11
- 1Open Settings (Windows key + I) and go to System > Activation.
- 2Next to "Change product key", click "Change".
- 3Enter your 25-character key and click "Next", then "Activate".
Windows 10
- 1Open Settings and go to Update & Security > Activation.
- 2Click "Change product key".
- 3Enter your key and follow the prompts to activate.
If you bought a Pro key and have Home installed, entering the Pro key in the same screen upgrades your edition. Save your work first; the upgrade requires a restart.
Microsoft Office
- 1Go to setup.office.com and sign in with your Microsoft account (or create one).
- 2Enter your 25-character product key and choose your country/region and language.
- 3After redeeming, go to account.microsoft.com/services and download Office from there.
- 4Open any Office app (for example Word) and sign in with the same account to finish activation.
Frequently asked questions
Windows says "This product key didn't work" (error 0xC004F050). Why?+
Usually the key does not match the installed edition, or it was mistyped. Check your edition under System > About and copy the key from your order page. If it still fails, open a dispute with the reason "Wrong key" and attach a screenshot.