Can a key be valid but fail because of Microsoft’s servers?

Yes, briefly — activation service outages happen a few times a year. Wait 30–60 minutes and retry before assuming the key is bad.

Does a hardware upgrade always break activation?

No. Replacing a disk or GPU usually survives; a motherboard swap is what triggers the hardware-change flow. A Microsoft-account-bound digital license recovers through the Troubleshooter.

Can I activate Windows without the internet?

Yes, by phone activation — Settings → Activation offers phone activation when online activation fails, useful for air-gapped installations.

My Office key fails on a Windows PC — why?

Office keys activate inside an Office app (File → Account), not in Windows Settings, and Office keys do not activate Windows. Match the key family to the product, then follow our Office activation guide .

When does a failed key qualify for replacement?

When the media, entry and usage checks above are clean and the key itself is rejected. That indicates a supply issue, which legitimate sellers replace free within the support window — 14 days for refund eligibility.

Windows Activation Failed: Common Causes, Error Codes and Fixes