How to Activate Windows 10/11 and Remove the Watermark

The “Activate Windows” watermark in the bottom-right of an unactivated Windows install isn’t just cosmetic — you also lose access to personalisation settings (wallpaper, accent colour, lock screen) and get occasional activation nags. The fix is a valid Windows 10 or 11 product key. This guide covers where to get one affordably, how to enter it correctly through changepk.exe, and how to upgrade from Home to Pro if that’s what you need. A Windows 10 Pro key activates both Windows 10 and Windows 11 on the same hardware, so buying a Win10 Pro key is usually the cheapest path.

Applies to: Windows 10 (22H2) and Windows 11 (22H2, 23H2, 24H2, 25H2) — Home and Pro editions
Last updated: April 2026

Disclaimer: This article contains affiliate links. If you make a purchase through these links, I earn a commission at no extra cost to you.

Key Takeaways

• Windows 7 and 8 keys no longer activate Windows 10 or 11. Microsoft closed the free-upgrade loophole — a current key is required.
• A Windows 10 Pro key activates Windows 11 too. Microsoft accepts Win10 Pro licences for Win11 Pro, so the cheaper Win10 key covers both.
• Activation is a Run command. Press Win + R, type changepk.exe, paste the key — no Settings maze required.
• Home to Pro is a one-step upgrade. Enter a Pro key on a Home system and Windows performs the edition upgrade automatically.

Quick Steps

1. Get a valid Windows 10 Pro OEM key from a reputable reseller like WhoKeys (discount code MTT25 for 25% off).
2. Press Win + R, type changepk.exe, press Enter.
3. Paste your key, click Next.
4. If you’re on Home and bought a Pro key, Windows prompts you to upgrade — click Start and wait.
5. Re-enter the Pro key after the edition upgrade finishes to complete activation. Watermark disappears on next reboot.

Why Activate?

You can run Windows 10 or 11 unactivated indefinitely — it’s one of Microsoft’s less-publicised policies. But the watermark stays, Personalisation settings are locked (you can’t even change the wallpaper through normal means), and some third-party apps refuse to run or warn you on launch. Activating removes all of that, links the licence to your motherboard’s hardware ID, and lets you reinstall Windows freely on the same PC in future.

If you upgraded from Windows 7 or 8 using my Windows 7 to 10 upgrade guide or Windows 8 to 10 upgrade guide, the upgrade still works — but the old key no longer grants a Windows 10/11 digital licence. You’ll need a current one to activate.

Buy a Key (WhoKeys + Discount Code)

WhoKeys is the reseller I use and sponsor on the channel. They sell OEM keys — these are single-PC licences that Microsoft allows resellers to redistribute (as opposed to volume-licence keys, which are not legal for retail). A Windows 10 Pro OEM key costs a fraction of a retail Windows 11 Pro key and activates both Windows 10 and Windows 11.

1. Open the Windows 10 Pro OEM key page on WhoKeys and click Buy Now.
2. Sign in or create an account (Google, Twitch, and YouTube sign-in all work).
3. At checkout, enter the promo code MTT25 and click Apply. Verify the discount was applied before paying.
4. Pay. The key is delivered instantly on the confirmation page under View Keys and Codes — and it’s also emailed and saved in your account’s purchase history.

Why WhoKeys and not eBay / Kinguin / random Reddit posts? OEM keys from unknown sources are often volume-licence keys resold illegally, and Microsoft can revoke them without warning. WhoKeys backs their keys with a warranty — if a key ever fails activation, support replaces it. I’ve tested their support process personally.

Enter the Key in Windows

You can enter the key through Settings → System → Activation → Change product key, but changepk.exe opens the same dialog more directly.

1. Press Win + R to open the Run dialog.
2. Type changepk.exe and press Enter.
3. Paste the 25-character key from WhoKeys and click Next.
4. If your current Windows edition matches the key (e.g. Pro key on Pro install), activation completes immediately.
5. Reboot. Watermark is gone and Settings → Activation shows Windows is activated with a digital licence.

Upgrading from Home to Pro

If you’re on Windows 10/11 Home and you paste in a Pro OEM key, changepk.exe will usually reply “The product key didn’t work.” That’s expected — Microsoft requires an intermediate step where an upgrade key tells Windows to switch editions first, then your purchased Pro key activates the upgraded system.

WhoKeys publishes two generic Home-to-Pro upgrade keys that Microsoft has made public for this purpose. These keys only perform the edition switch — they don’t activate Windows on their own.

1. Open changepk.exe (Win + R → changepk.exe).
2. Paste one of the upgrade keys below and click Next:

Upgrade key 1: JNB6J-DBPVV-GYTC6-YBX9D-FM49G
Upgrade key 2: NCD4Q-C2GMT-QDB66-6PGK6-V6DGT

3. Windows prompts you to start the upgrade. Click Start. The PC reboots once or twice and the edition switches from Home to Pro. Your files and applications are preserved.
4. After the upgrade completes, run changepk.exe again and this time paste the real Pro key you purchased from WhoKeys.
5. Click Next. Activation completes, watermark disappears, and Pro features (Hyper-V, BitLocker, Group Policy Editor, Remote Desktop server) become available.

Verify Activation from the Command Line

If the Settings panel isn’t giving you a clear answer, you can check activation status directly with the built-in slmgr tool. Run from an elevated PowerShell or Command Prompt:

slmgr /xpr

“The machine is permanently activated” confirms the digital licence is in place. For a full licence dump (edition, partial product key, grace period, activation ID):

slmgr /dli
slmgr /dlv

Why a Windows 10 Key for Windows 11?

When Microsoft launched Windows 11, they kept the same licensing tier as Windows 10 — a valid Windows 10 Pro key activates Windows 11 Pro, and a Windows 10 Home key activates Windows 11 Home. The digital licence is tied to the motherboard, not the OS version, so if you later upgrade from 10 to 11 (see my Windows 10 to 11 upgrade guide), activation carries over automatically.

At the time of writing, a Windows 10 Pro OEM key on WhoKeys is significantly cheaper than a Windows 11 Pro key, so it’s the same licence, cheaper path.

Related Guides

• Upgrade Windows 10 to Windows 11
• Enable Windows 10 Extended Security Updates (ESU) free
• Install Windows 11 on unsupported hardware
• Install Group Policy Editor on Windows Home (before upgrading to Pro)
• Winhance — post-activation optimisation

Frequently Asked Questions

Will a Windows 7 or 8 key still activate Windows 10/11?

No. Microsoft ended the free-upgrade path that honoured Windows 7 and 8 keys as Windows 10 digital licences. The upgrade from 7/8 to 10 still works (see my Windows 7 upgrade guide), but activation requires a current Windows 10 or 11 key.

Is buying OEM keys from resellers legal?

Buying genuine OEM keys is legal. Microsoft sells OEM licences in bulk to system builders and authorised resellers, who then sell them individually — that’s the cheap keys you see online. What’s not legal is reselling volume-licence keys (MAK keys from enterprise agreements), and those sometimes end up on grey-market sites. Stick to resellers with warranties and support. WhoKeys falls into that category; random Reddit DMs do not.

What if the product key doesn’t work?

Check three things in order: you’re entering the key without spaces, your current Windows edition matches the key (Pro key → Pro install), and the key is for the version you’re activating (Win10 Pro key works for both Win10 and Win11 Pro, but a Win10 Home key won’t activate Win11 Pro). If all three check out and it still fails, contact the reseller — WhoKeys replaces faulty keys.

Can I upgrade Home to Pro for free with a Pro key?

Yes, once you own a Pro key. The two-step process (generic upgrade key, then your real Pro key) is described in the Upgrading from Home to Pro section above. The generic upgrade keys Microsoft publishes don’t activate Windows — they only trigger the edition switch. The paid Pro key completes activation after the upgrade.

Do I need Pro or is Home enough?

Home is fine for most users. Pro adds BitLocker drive encryption, Hyper-V virtualisation, Remote Desktop server (not client — Home can still connect to remote machines), Group Policy Editor, and domain-join support. If you run VMs, encrypt drives, or manage a home lab, Pro is worth it. If you just browse, game, and use office apps, Home is sufficient. Note: you can install Group Policy Editor on Home separately if that’s your only Pro need.

What if I lose my product key?

WhoKeys stores every key in your account’s purchase history, so sign in and retrieve it there. Windows itself also remembers the licence as a digital licence tied to your Microsoft account and hardware ID — you don’t need to re-enter the key when reinstalling Windows on the same machine, Windows reactivates automatically once it’s online.

What about Windows 10 end of support in October 2025?

Windows 10 stops receiving security updates in October 2025 unless you’re enrolled in ESU. Your Windows 10 Pro key stays valid and the system keeps working — it just doesn’t get patches. Two options: upgrade to Windows 11 (same key carries over), or stay on 10 and enrol in free ESU for an extra year of security updates.