How to check whether the licenses you own are valid

You check whether the licenses you own are valid by comparing three things: the invoice from an authorized reseller, the edition of the installed software and the key it was activated with. For subscriptions such as Microsoft 365, you check in the company account: every user must have a license assigned.

Most companies use software from the Microsoft portfolio, namely Windows and Office (today, mostly Microsoft 365). Like any software, these programs are protected by Law 8/1996 on copyright and related rights, Romania’s copyright law, and their validity depends on several factors you need to know.

When we wrote this article, the most popular licensing options among small and medium-sized companies were OEM, FPP and GGK licenses. Larger companies also used volume licensing, for example OVS (Open Value Subscription), which we won’t discuss much here. The basic rules below still apply today, and at the end you’ll find what has changed since.

When are Microsoft licenses used and what are their limitations?

FPP (Full Packaged Product)

This is the simplest (though not the cheapest) way to license a computer. Specifically, an FPP license (also called “retail”) is the right granted by the manufacturer to use the license you bought on any computer you want.

Advantages:

• it can be bought at any time (before or after buying the computer it will be installed on);
• it can be moved from one computer to another (note: it can’t run on several computers at the same time).

Disadvantages:

• it doesn’t give you access to newer versions of the software;
• its price is the highest of all the licensing options.

How do you check that it’s valid?

• The license is bought by the company that uses it: you can’t use a license bought or owned by another company, and the invoice must be shown in case of an inspection.
• It must be bought from an authorized distributor: not every company is allowed to sell licenses.
• The edition on the license (for example Windows 11 Home) must be exactly the same as the one installed on the computer. If Windows 11 Pro is installed on the computer, the Home license isn’t valid.
• The key on the license must be the same as the key the software was activated with on the computer. It isn’t enough for the number of licenses to equal the number of computers using the software.

OEM (Original Equipment Manufacturer)

OEM licenses are the most common among small and medium-sized companies because they’re cheaper than FPP licenses. Originally, only licenses preinstalled by the computer manufacturer were considered OEM (hence the name), but they can also be installed by companies that assemble computers.

Advantages:

• a lower purchase cost.

Disadvantages:

• it doesn’t give you access to newer versions of the software;
• it doesn’t let you move the license from one computer to another;
• it must be bought together with the computer it will be installed on.

How do you check validity?

• The purchase must be made from a company authorized to sell such licenses.
• The license is valid only for the company that bought it and only for the computer it was bought for (proven by the invoice).
• Both the computer and the license must appear on the same invoice. Licenses bought on separate invoices aren’t valid, even if they were bought from the same supplier on the same day.
• It’s valid only if bought together with a computer (desktop or laptop), not with other equipment (monitor, keyboard, mouse, etc.).
• On older computers, a sticker (certificate of authenticity, COA) with the license key must be attached to the case, and the key on the sticker must match the one used for activation and the one on the invoice. On computers sold with Windows 8 or later, the key is stored in the motherboard firmware and activates automatically, with no sticker.
• The edition installed on the computer must be exactly the one on the invoice. If the license bought was for Windows 11 Home, Windows 11 Pro can’t be installed on the computer.

GGK (Get Genuine Kit)

This is a type of licensing offered by Microsoft to bring software used without a valid license into compliance. Microsoft also offers GGK for Windows 11.

Advantages:

• a lower cost than an FPP license;
• you can license any computer you own, even if it wasn’t bought together with the license.

Disadvantages:

• it can’t be moved from one computer to another;
• it doesn’t give access to later versions released by Microsoft;
• it can’t be bought together with new computers.

How do you check validity?

• It can be installed only on computers that have a preinstalled license that isn’t valid (either because it’s no longer valid or because it wasn’t bought properly).
• You must be able to prove both the purchase of the GGK license and the existence of a license on that computer. GGK is usually used for refurbished computers that originally had a license which became invalid after the computer was bought by another company, because an OEM license isn’t transferable.
• The key on the license must match the one installed on the computer.
• The edition on the license must be the same as the one installed on the computer.

Second-hand licenses can be sold legally in the European Union only under certain conditions. If you’re offered such licenses, always ask for the documents that prove where they came from.

What has changed in Microsoft licensing since 2012?

• Office is now bought mostly as a subscription. Microsoft 365 is licensed per user, not per computer: one user can use their license on several devices. Perpetual versions still exist (Office 2024, Office LTSC 2024), but Office 2016 and 2019 stopped receiving updates on October 14, 2025.
• Volume licensing has moved to the CSP program (Cloud Solution Provider). The Open License program, used by many small companies, ended on January 1, 2022.
• Windows 10 no longer gets free security updates as of October 14, 2025. Compatible computers can move to Windows 11 for free, and since 2023 Windows 7 and 8.1 licenses no longer activate Windows 10 or 11 for free. See how to upgrade.

How do you quickly check your company’s licenses?

A few checks you can do yourself:

• Windows: Settings > System > Activation shows whether Windows is activated and which edition is installed. The slmgr /dli command, run in Command Prompt, also shows the license type (OEM, retail or volume).
• Microsoft 365: in the Microsoft 365 admin center, under Billing > Licenses, you can see how many licenses the company has and who they’re assigned to. Licenses assigned to former employees can be freed up.
• Documents: keep the license invoices for each computer in one place. During an inspection, the invoice is your proof.

A complete inventory of your computers and installed software makes checking much simpler. Your first IT audit from RezolvIT is free and includes an inventory of the company’s hardware and software. For help choosing the right licensing solution, contact us.