How to Activate Windows 10 and 11: Settings, Command Line, Phone Activation and Troubleshooting

Activation is how Windows confirms that the installation is licensed. Done properly it is a one-time step that survives updates, restarts and even reinstalls on the same hardware. This guide covers all four activation methods, explains the digital licence that Windows 10 and 11 create after the first activation, and decodes the error codes that appear when something is wrong. It applies to every edition in our Windows category, from Windows 11 Home to Windows 11 Pro and the LTSC editions.

Before activating: two checks

Edition. Settings, System, About shows the installed edition. It must match the key. A Pro key on a Home installation triggers an in-place upgrade to Pro, which is fine; a Home key on a Pro installation is refused. See our guide to edition mismatches.

Network. Online activation needs a working internet connection. Corporate proxies and some VPNs block it; disconnect the VPN for the activation step.

Method 1: Settings (the normal route)

1. Open Settings, System, Activation (Windows 11) or Settings, Update & Security, Activation (Windows 10).
2. If the page already says “Windows is activated”, you are done; the key was applied during setup or the digital licence was found.
3. Otherwise click Change product key, paste the key from your delivery email, and click Next.
4. Windows contacts Microsoft’s activation service. Within seconds the page updates to “Windows is activated”.

Method 2: Command line (slmgr)

The Software Licensing Management Tool exposes everything the Settings page does and more. Open Command Prompt or Terminal as administrator.

Command	What it does
slmgr /ipk XXXXX-XXXXX-XXXXX-XXXXX-XXXXX	Installs the product key
slmgr /ato	Activates online
slmgr /xpr	Shows whether activation is permanent
slmgr /dli	Shows licence status and partial key
slmgr /dlv	Detailed licence information including channel and rearm count
slmgr /upk	Uninstalls the current key (before moving a licence)
slmgr /cpky	Clears the key from the registry
slmgr /rearm	Resets the licensing state (used for corrupt licence stores)

A typical sequence on a fresh install is /ipk, /ato, /xpr. If /ato returns an error code, note it and use the table at the end of this guide.

Method 3: Telephone activation

When online activation refuses the key with a 0xC004 code, Microsoft’s automated telephone service verifies the same key through a different channel. Press Windows + R, type slui 4, press Enter, choose your country, and the window shows a toll-free number and a nine-group installation ID. Call, read the installation ID, and type the confirmation ID the system reads back. Activation is then permanent.

If you prefer not to call, send the installation ID to us through the free Microsoft Confirmation ID service and we return a confirmation ID by email. Our guide to keys reported as used or blocked explains why online activation sometimes refuses a genuine key.

Method 4: Digital licence and the Activation troubleshooter

After the first successful activation, Microsoft stores a digital licence tied to the PC’s hardware. Reinstalling Windows on the same hardware activates automatically from that licence, with no key needed; choose “I don’t have a product key” during setup and pick the same edition.

Linking the licence to a Microsoft account (Settings, Accounts, Your info, sign in) adds a safety net for hardware changes. After replacing the motherboard, open Settings, System, Activation, click Troubleshoot, choose “I changed hardware on this device recently”, sign in, select the PC from the list and click Activate. If the troubleshooter cannot find the PC, enter the product key again and use telephone activation if needed.

Activating Windows 11 with a Windows 10 key

Windows 11 accepts Windows 10 keys for the same edition. A Windows 10 Pro key activates Windows 11 Pro; a Windows 10 Home key activates Windows 11 Home. Enter it through any of the methods above.

Activating Enterprise and LTSC editions

Windows 11 Enterprise LTSC 2024 and IoT Enterprise LTSC 2024 activate with the same slmgr /ipk and /ato commands. These editions are installed from their own media, not the consumer ISO, and a consumer key will not activate them. If slmgr /dlv shows a VOLUME_KMSCLIENT channel and activation fails with 0xC004F074, the installation is looking for a company KMS server; installing your key with /ipk switches it to the correct channel.

Error codes decoded

Code	Meaning	Fix
0xC004F050	Key invalid	Edition mismatch or typo; check Settings, System, About; paste the key
0xC004F210	Key is for a different edition	Install the matching edition
0xC004C008	Key exceeded activation count	Release on the old PC with slmgr /upk; telephone activation
0xC004C003	Key blocked	Telephone activation; replacement if phone refuses
0xC004C060	Online activation denied	Telephone activation
0xC004F074	No KMS server found	Enter retail key with slmgr /ipk, then /ato
0xC004E003	Licence evaluation failed	slmgr /rearm, restart, enter key again
0x803FA067	Not activated after hardware change	Activation troubleshooter with Microsoft account
0x803F7001	No licence found	Enter the key manually
0x8007007B	Network error during activation	Check connection and VPN; retry or telephone
0xC004F213	No product key found	Key was never applied; enter it

If the code is not in the table, our article on “This product key didn’t work” covers the remaining cases, and support can look it up from a screenshot.

Removing the “Activate Windows” watermark

The watermark in the bottom-right corner appears when Windows is not activated and disappears a few minutes after successful activation. If it persists after activation, restart once; if it still shows, run slmgr /xpr to confirm the state and slmgr /ato to re-trigger. Tools that hide the watermark without activating are not a fix and often cause update problems.

Moving a licence to a new PC

Retail licences, which is what we sell, can be moved. On the old PC run slmgr /upk and slmgr /cpky. On the new PC install Windows, enter the key, and activate; use telephone activation if the online attempt is refused because the old activation is still counted. OEM licences that came with a branded PC cannot be moved.

Checklist

1. Confirm the edition matches the key.
2. Settings, System, Activation, Change product key, or slmgr /ipk and /ato.
3. Confirm with slmgr /xpr: “permanently activated”.
4. Link to a Microsoft account for easy re-activation.
5. If refused: decode the error, then telephone activation or our Confirmation ID service.

Every Windows licence from GetDigiMarket is delivered within seconds and covered by the 180-day money-back guarantee.

What activation does and does not check

Activation confirms the key is valid for the edition and records the hardware fingerprint against the licence on Microsoft’s servers. It does not inspect your files, does not need to be repeated after updates, and does not phone home continuously; Windows re-validates quietly on a schedule and only shows a message if the licence state changes, for example after a motherboard replacement. Activation also does not depend on a Microsoft account: a local account activates in exactly the same way. The account link is an optional convenience for re-activation.

Activating several PCs with one multi-device key

Our 5-PC licences, such as Windows 11 Pro for 5 PCs, use one key on all five machines. Enter the same key on each PC with any method above; each activation counts against the five. If the sixth attempt, or a reinstall that was not released with slmgr /upk, is refused with 0xC004C008, telephone activation generally completes it, because the count is checked less strictly through that channel. Keep a note of which machines have used the key so that the count stays accurate.

Checking activation on a PC you did not set up

On a second-hand or inherited PC, run slmgr /dlv. The Description line shows the channel: RETAIL, OEM_DM (a licence embedded by the manufacturer), or VOLUME_KMSCLIENT. An OEM_DM licence belongs to the machine and is fine to keep. A VOLUME_KMSCLIENT entry on a home PC with an expiry date under “Volume activation expiration” means the machine was activated against a KMS server (sometimes an illegitimate emulator) and will lose activation when the 180-day window ends; enter a retail key to put it on a permanent licence.

Activation and Windows updates

Windows Update does not require activation, but an unactivated installation shows the watermark, limits personalisation settings, and nags periodically. Activate first, then run updates, because a cumulative update occasionally changes the activation state on an unactivated system and produces a confusing extra error. On an activated system, updates never require re-activation; the digital licence survives every feature update, including the move from 24H2 to 25H2.

Activation on virtual machines

Windows running inside Hyper-V, VMware or VirtualBox activates in exactly the same way, with one practical note: a virtual machine’s hardware fingerprint changes if you alter its virtual hardware significantly or move it to a different host, which can trigger a re-activation prompt. Linking the licence to a Microsoft account and using the Activation troubleshooter handles this as it does on a physical PC. Each virtual machine needs its own licence; a single-PC key covers one installation whether physical or virtual.

Related guides: Windows 11 Home vs Pro and What is Windows LTSC?.

Frequently asked questions