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Help · Windows

My Windows 11 key does not work: what to do?

By Baptiste Morin, technician at MAO Informatique Updated on Reading time: 2 min
Quick answer

In most cases the problem comes from the edition (Home or Pro), a typing error or the Internet connection. Follow the six checks below, then contact the seller with the error code if Windows is still not activated.

Six checks, in order

  1. Does the edition match?

    A Pro key does not apply as is to Home. See error 0xC004F050.

  2. Is the key entered correctly?

    Copy and paste the key from the email. Avoid spaces at the start or end.

  3. Are you connected to the Internet?

    Activation goes through Microsoft’s servers.

  4. Use the troubleshooter

    Settings, System, Activation: the “Troubleshoot” button appears when Windows is not activated.

  5. Retry activation from the command line

    In a Command Prompt opened as administrator: slmgr /ipk YOUR-KEY then slmgr /ato.

  6. After a hardware change

    Replacing the motherboard may require reactivation: use “Troubleshoot”, then “I changed hardware on this device recently”.

Read the error code

Code shownMost likely causeHelp page
0xC004F050, 0xC004F034Key for another edition or version, or a typoError 0xC004F050
0xC004F074, 0x8007232BWindows is looking for a company KMS serverError 0xC004F074
0xC004C008Key already used on another deviceActivation errors
0xC004F213, 0x803F7001Hardware change or licence not foundActivation errors
0x80072F8FDate, time or connectionActivation errors

Check what Windows has actually recorded

In the command prompt, slmgr /dli shows the edition and channel of the installed licence (RETAIL, OEM, VOLUME_MAK or VOLUME_KMSCLIENT). If you see VOLUME_KMSCLIENT on a personal PC, an old generic key is still installed: replace it with your key using slmgr /ipk, then slmgr /ato. More details: check a Windows or Office key.

Still stuck?

Write to us with the error code and a screenshot, from the chat or the Contact page. The key is replaced or refunded under our guarantees.

Frequently asked questions

Why does Windows say the key is not valid?
Most often, the edition does not match, the key was mistyped or there is no Internet connection.
What is slmgr /ato for?
This command tells Windows to activate the installed key online. It is used after slmgr /ipk.
My PC is new and came with Windows: do I need a key?
If Windows is already activated by the manufacturer, no. The key is for a PC without a licence or to change edition.
My key worked, then Windows deactivated: why?
Usually after a hardware change (motherboard) or because Microsoft blocked the key. Note the error code: if the key came from us, it is replaced or refunded.
Can I activate Windows 11 by phone?
No. Since 3 December 2025, Microsoft has replaced phone activation with an online activation portal.

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