“Is this key genuine?” is the right question to ask — before buying if possible, and definitely after activating. Here is what you can actually verify at each stage, using nothing but built-in tools.

Before buying: verify the seller, not the key

No public Microsoft tool lets you pre-check an unused key's validity — only activation does that. So pre-purchase diligence is about the seller:

  • License channel is stated. Retail, OEM, or volume — a listing that names the channel is a listing by someone who understands what they are selling.
  • Replacement warranty with a stated window. This is the seller putting money behind the key's validity.
  • Reachable support. Send a pre-sales question. If nobody answers before the sale, nobody will answer after it.
  • Sane pricing story. Cheap is normal in this market (see our gray-market guide); what should worry you is a seller who cannot explain their own product.

After activation: what Windows tells you

1. Confirm activation status

Settings → System → Activation should read “Active,” ideally “activated with a digital license.” Or run slmgr /xpr — a genuine permanent license reports “The machine is permanently activated.” A message about expiration means a KMS-style activation, which is not what a retail purchase should produce.

2. Check the license channel

Run slmgr /dli in an elevated prompt. The description line shows the channel:

  • RETAIL — full retail license, transferable to new hardware.
  • OEM_DM / OEM_SLP — OEM, tied to this machine.
  • VOLUME_MAK — volume license, permanently activated.
  • VOLUME_KMSCLIENT — activates against a KMS server and renews every 180 days. If you bought a “lifetime retail key” and see this, you did not get what you paid for.

3. Watch for the KMS-tool red flag

Some dishonest sellers “activate” machines with unauthorized KMS emulators instead of real keys. Signs: activation that expires after ~180 days, a KMSCLIENT channel you never chose, or scheduled tasks/services with KMS-related names you did not install. That is not a genuine license at any price.

4. For Office

In the Office folder, cscript ospp.vbs /dstatus prints license family, channel and status per installed product — the Office equivalent of slmgr.

Tip: run these checks on day one, screenshot the results, and file them with your delivery email. If anything changes later, you have a dated record for the warranty claim.

If verification fails

Wrong channel, expiring activation, or a blocked key: contact the seller with your evidence and ask for replacement under the stated warranty. A legitimate store resolves this without drama — it is a routine part of the business.

We publish the license channel on every product page and back every key with a replacement warranty. Browse the store and verify us against this very checklist.