How to Back Up a Windows 10 Product Key Safely

To back up a Windows 10 product key, first check whether your copy uses a key: many PCs use a digital license instead, with no 25-character code to retrieve. Save a real key in a protected note with its Windows edition. If you use a digital license, link it to your Microsoft account before reinstalling.

Windows 10 support ended on October 14, 2025; a saved key does not restore updates. See Microsoft’s support information if you are deciding whether to keep using it.

1. Check your edition and activation type

Before copying anything, record whether the PC runs Windows 10 Home or Pro. Open Settings > System > About and look under Windows specifications. Then open Settings > Update & Security > Activation to see the activation status.

• Windows is activated with a digital license linked to your Microsoft account: the account is already associated with the license.
• Windows is activated with a digital license: the PC is activated, but the license is not linked to your Microsoft account.
• Windows is activated: check how Windows was purchased; you may have a product key, and the account may not be linked.

A digital license is associated with the device and needs no key entry. The edition still matters: reinstall Home for a Home license or Pro for a Pro license. A key for one edition will not activate the other.

2. Find the key that matches how you got Windows

Microsoft’s product-key guide explains that the key’s location depends on the purchase method:

• Windows came with a new PC: check the device packaging or Certificate of Authenticity (COA). Some PCs store an OEM key in firmware.
• You bought a boxed copy: check the card or label inside the Windows packaging.
• You bought a digital retail copy: look in the retailer’s confirmation email or online order locker. For a Microsoft online-store purchase, check the Microsoft account order history and confirmation email.
• You upgraded through Microsoft Store or received a free upgrade: you may have a digital license rather than a separate key.

On a PC that has an embedded OEM key, PowerShell can query the firmware value. Open PowerShell and run this read-only command:

Get-CimInstance -ClassName SoftwareLicensingService | Select-Object -ExpandProperty OA3xOriginalProductKey

PowerShell displays a key only if one is stored in firmware. This query cannot reveal a digital license or a retail key in an email. A blank result does not mean Windows is unlicensed; it may have no firmware key. If you upgraded from Home to Pro, the query may show the original Home key while Pro uses a digital license.

3. Save a product key securely

When you locate a valid 25-character key, copy it carefully into a password manager’s secure note or an encrypted file. Include the Windows edition, the PC it came with, the purchase source, and where the receipt or order confirmation is stored. These details help distinguish an original OEM key from a later upgrade.

Keep a second protected copy, such as on an encrypted backup drive. Avoid shared folders, ordinary unencrypted notes, email, or screenshots. Treat the key as a secret; activation still follows Microsoft’s license terms.

4. Link a digital license to your Microsoft account

If Activation says Windows is activated with a digital license but does not say it is linked, sign in to Windows with an administrator account that uses your Microsoft account. Go back to Settings > Update & Security > Activation, select Add an account, and sign in. When it is linked, the page should say that Windows is activated with a digital license linked to your Microsoft account.

Linking can help you reactivate after a major hardware change, such as replacing a motherboard. It is not a product-key backup or a transfer guarantee; eligibility depends on the license. Ask your administrator about organization-managed devices.

Use the backup when reinstalling Windows

Before reinstalling, confirm activation and edition, and keep your key or account details accessible outside the PC. With a digital license, install the same edition and choose I don’t have a product key if Setup asks. After connecting to the internet, sign in with the linked Microsoft account so Windows can reactivate. Enter a product key during Setup or later at Settings > Update & Security > Activation > Change product key.

Microsoft’s reinstallation instructions emphasize choosing the edition that matches your license. If Windows does not reactivate after a hardware change, try the Activation troubleshooter while signed in to the linked account.