Retail vs OEM vs Volume Keys at a Glance

• Retail (FPP): the license belongs to you, not to a specific computer. You can uninstall it from an old PC and activate it on a new one. Activates directly with Microsoft. This is the type sold at KRBKeys.
• OEM: the license locks to the first motherboard it activates on, and you cannot move it to another PC. This is the type that comes preinstalled on laptops and prebuilt desktops. Sellers also offer it as "system builder" keys.
• Volume (KMS or MAK): licenses for organizations with many PCs. KMS keys activate against a company server and must re-check in every 180 days. MAK keys activate with Microsoft, but each activation uses a slot from a pool that the organization owns. Organizations buy them, not individuals.

Retail Keys: What You Get

A retail key is a full, standalone license. Microsoft's terms allow you to transfer it to a different computer as long as it is only active on one PC at a time. In practice this means you can buy a Windows 11 Pro retail key today, use it for years, and when you build or buy a new PC, deactivate it on the old one and activate it on the new one. A retail key also works with both clean installs and upgrades: it can turn Windows 11 Home into Pro in minutes without reinstalling.

Windows links a retail key to your hardware and, if you sign in, to your Microsoft account. That digital license makes reinstalling Windows later automatic; you rarely need to type the key again. Office can link retail keys to your Microsoft account for the same reason.

OEM Keys: Cheaper, but Locked to One Motherboard

OEM keys are what manufacturers like Dell, HP and Lenovo embed in the firmware of new PCs. Sellers also offer them as "OEM" or "system builder" keys at lower prices. The catch is in the license terms: an OEM key locks permanently to the first motherboard it activates. If you replace the motherboard, move to a new PC, or the board fails, you lose the key. You also cannot use OEM keys to upgrade an existing edition (for example Home to Pro); they only work for a clean install.

If you plan to keep the same PC for its whole life and never upgrade the board, an OEM key can be fine. If there is any chance you will move to a new computer, a retail key is the better buy, and the price difference is usually small.

Volume Keys (KMS and MAK): Why They Cause Problems for Home Users

Microsoft designed volume licensing for companies and schools that manage hundreds of PCs. There are two kinds:

• KMS (Key Management Service): the PC activates against the organization's own KMS server, not Microsoft, and must reconnect to that server every 180 days to stay activated. However, a KMS key on a home PC has no server to talk to. As a result, it either never activates or shows errors like 0xC004F074 ("the activation server could not be contacted"). Some "cheap key" sellers use KMS keys or tools that create a fake local server. These activations break after a few months and violate Microsoft's terms.
• MAK (Multiple Activation Key): activates with Microsoft directly, but every activation uses one slot from a pool that belongs to an organization. When the pool runs out or Microsoft blocks the key, every PC that used it loses activation. This is the usual cause of error 0xC004C060 ("the product key has been blocked") and sudden "Windows is not activated" messages months after purchase.

Microsoft sells KMS and MAK keys to organizations, not to individuals. That is why they cause most activation complaints about cheap keys found on marketplaces. Microsoft's How to Tell page explains how to recognize genuine software.

How to Check Which Type of Key You Have

On Windows, open a Command Prompt as administrator and run:

1. Type slmgr /dlv and press Enter.
2. Wait a few seconds for the Windows Script Host window.
3. Look at the Description line. It ends with the channel: RETAIL channel, OEM_DM channel (manufacturer-embedded), OEM_COA_NSLP channel (system builder), VOLUME_KMSCLIENT channel (KMS) or VOLUME_MAK channel (MAK).

For Office, open any Office app, go to File → Account; a retail or Microsoft-account license shows "Product Activated" with your account, while volume licenses typically show a generic "Microsoft Office Professional Plus" product name without an account. You can also run cscript "C:\Program Files\Microsoft Office\Office16\ospp.vbs" /dstatus in an administrator Command Prompt and read the LICENSE NAME line, which includes "Retail," "OEM" or "Volume."

Retail vs OEM: Which Type Should You Buy?

For a personal or small-business PC, a retail key is the right choice: it is transferable, it activates directly with Microsoft, it supports upgrades like Home to Pro, and it does not depend on a server or a shared pool that can be exhausted. The price difference compared to OEM is small, and compared to the risk of a blocked volume key, it is not worth saving a few dollars.

All Windows and Office keys sold at KRBKeys are genuine retail licenses. Windows 11 Pro keys are delivered instantly after payment; other keys arrive by email with the official Microsoft download link. If a key ever fails to activate, our support team replaces it.

If You Bought Your Key From KRBKeys

Your key is a retail license. If Windows or Office shows an error during activation, check the error code against our activation guides, or email support@krbkeys.com with your order number and a screenshot. We reply within 24 hours.