Activate Windows 10 with your product key

Activation confirms with Microsoft that your copy of Windows is genuine and not used on more PCs than the licence terms allow. This guide assumes Windows is already installed. If not, start with Set up Windows 10.

Your key and your edition

Your 25-character product key is in your order confirmation email and in your Lizensa account under My Library. This guide shows it as XXXXX-XXXXX-XXXXX-XXXXX-XXXXX.

Your order includes one of these key types:

• Retail key for Windows 10 Home, Pro, Pro N or Pro for Workstations. Microsoft gives the device a digital licence based on the valid key you enter.
• Volume key (MAK, Multiple Activation Key) for Windows 10 Pro MAK and the volume editions, such as Enterprise LTSC 2021 MAK. Microsoft describes a MAK as a key that works like a retail key but can activate a set number of computers. Each activation counts against that number. Microsoft calls MAK and retail activation perpetual.
• Windows 7 Professional or Windows 8.1 Pro key. You receive the key only, with no installer. Microsoft no longer offers downloads for these versions, so you need your own installation media. If you have none, contact our support before you install. Each key activates its own Windows version.

What Microsoft's support dates mean for activation:

• Windows 10 Home, Pro and Pro for Workstations: support ended on 14 October 2025, and 22H2 is the final version. Activation still works. Microsoft's consumer Extended Security Updates (ESU) programme can protect a Windows 10 device until 12 October 2027. Support for Windows 10 IoT Enterprise also ended on 14 October 2025.
• Enterprise LTSC: LTSC 2021 until 12 January 2027, LTSC 2019 until 9 January 2029, IoT Enterprise LTSC 2021 until 13 January 2032. Support for 2015 LTSB ended on 14 October 2025, and for 2016 LTSB on 13 October 2026.
• Windows 7 ended on 14 January 2020, Windows 8.1 on 10 January 2023, with no ESU programme for 8.1.

Does your key fit the installed edition?

For Windows 10 Home, Pro, Pro N, Home N, Pro for Workstations and Pro MAK, your download link is in your order email and in your account. It points to Microsoft's Windows 10 download page. For Enterprise LTSC and LTSB, including IoT Enterprise LTSC 2021, your LTSC installer link follows in your order email and in your account; until it appears, contact our support before you install. Do not use the Media Creation Tool for these editions, because Microsoft states that it does not contain Windows 10 Enterprise. Windows 10 IoT Enterprise (OEM) is key only; contact our support before you install.

A key activates only the edition it was issued for. A Pro key does not activate Home in place. It upgrades Home to Pro, which Microsoft supports through Change product key; restart the PC afterwards. An Enterprise LTSC key needs Enterprise LTSC installed.

The Activation page under Start > Settings > Update & Security > Activation shows the installed edition next to Edition.

Is Windows fully installed?

Online activation needs an internet connection. If Windows is not set up yet, follow the setup guide first. Sign in with an account that has administrator rights.

Activate Windows 10

Retail key: in Settings

1. Select Start > Settings > Update & Security > Activation.
2. Select Change product key.
3. Enter your key and select Next, then Activate.

When it succeeds, the Activation page shows one of the activated messages listed under Check that it worked. If you entered your key during Setup, check the activation status on the same page first.

Then link your Microsoft account: on the same page select Add an account and sign in. This links the account to the device's digital licence. After a mainboard change, the Activation troubleshooter can then reactivate Windows.

Volume key (MAK) and Enterprise editions

The Change product key route above also accepts a MAK. If it refuses the key, or if Windows reports an activation server it cannot reach, use the command line. Volume media from Microsoft can carry a generic key (GVLK) for company KMS servers. With that key, Windows tries a KMS host instead of Microsoft's activation service. Your own MAK replaces it.

1. Select Start, type cmd, right-click Command Prompt and select Run as administrator.
2. Install your key:

slmgr /ipk XXXXX-XXXXX-XXXXX-XXXXX-XXXXX

3. Restart the PC, as Microsoft advises after a key change. Open Command Prompt as administrator again.
4. Activate online:

slmgr /ato

Then check the result as shown under Check that it worked.

No internet on this PC?

You can activate offline with an Installation ID. Microsoft asks you not to call the phone number Windows shows. Use the Product Activation Portal instead, from any device with internet.

1. On the PC, select Start > Settings > Update & Security > Activation, then Activate by Phone.
2. Choose your country or region and select Next. Windows shows your Installation ID.
3. On another device, open Microsoft's Product Activation Portal and sign in. Select Activate a Microsoft Product > Windows > Windows 10, enter the Installation ID and select Submit.
4. The portal returns a Confirmation ID. Back on the PC, select Enter Confirmation ID, type it and select Activate Windows.

If Activate by Phone is missing, use Command Prompt as administrator. The first command shows the Installation ID. The second one takes the Confirmation ID, typed without hyphens or spaces in place of the placeholder:

slmgr /dti
slmgr /atp CONFIRMATIONID

If the portal does not accept the Installation ID of a volume key, Microsoft's activation centres handle MAK activation by phone.

Windows 7 and Windows 8.1

• Windows 7 Professional: open Control Panel > System and Security > System and select Activate Windows now. Enter the key when Windows asks. Offline, choose Use the Automated Phone system there instead.
• Windows 8.1 Pro: open PC settings and select Activate Windows. Offline, choose Contact customer support.

Offline, both show an Installation ID after you pick your country or region. Submit it in the Product Activation Portal under Windows > Windows 7 or Windows 8.1 or 8, then enter the Confirmation ID in Windows.

Check that it worked

1. Open Settings > Update & Security > Activation.
2. The status reads "Windows is activated", "Windows is activated with a digital license" or "Windows is activated with a digital license linked to your Microsoft account".

From Command Prompt you can also run:

slmgr /dli

The command shows the installed edition and its licence status.

If something goes wrong

0xC004F074 or 0x8007232B. Microsoft names two causes: an Enterprise key entered on Home or Pro, or a work device that cannot reach its activation server. If you installed from volume media, Windows may still run on the generic KMS key; replace it with your MAK using the commands above. Check the edition first. Details: error 0xC004F074 and error 0x8007232B.

0xC004F050. Microsoft says the key can't be used to activate Windows. Check that the installed edition matches your order and enter the key again under Change product key. See error 0xC004F050.

0xC004C003 or 0xC004C008. With 0xC004C003, Microsoft treats the key as invalid. With 0xC004C008, the key was used on another device or on more devices than the licence terms allow. Do not try other keys. Contact our support with your order number. Background: error 0xC004C003, error 0xC004C008.

Activation lost after a new mainboard (0xC004F213). After a significant hardware change, such as a new mainboard, Windows may need to be activated again. With a linked Microsoft account, select Troubleshoot on the Activation page and then I changed hardware on this device recently. Without a digital licence, enter your product key again. See error 0xC004F213.

0x803F7001 after a reinstall. Windows found no valid licence for this PC. Enter your key under Change product key. See error 0x803F7001.

Windows 7 or 8.1 shows an error code. Note it and contact our support; Microsoft no longer offers technical support for these versions.

Still stuck? Contact our support with your order number and the exact message you see.