Is it legal to buy a used Windows or Office product key?

In the US, the resale of a genuine license that the original owner no longer uses is generally defended under the first-sale doctrine, and EU law allows resale of used licenses under UsedSoft v Oracle. The answer can depend on the license terms and where you are, so take legal advice if your situation is unusual.

What is the difference between a used license and a pirated key?

A used license is a genuine Microsoft product key that a business bought, used and then stopped using, so it changes hands once. A pirated or misused key is generated, leaked, or sold to many buyers at the same time, and it often stops working when Microsoft blocks it.

Do pre-owned Microsoft licenses receive updates?

Yes. Once a genuine key is activated, the software receives Microsoft updates and security patches in the same way as any other license, for as long as Microsoft supports that version. Check the version's support end date before you buy.

Does Microsoft endorse resellers of used licenses?

No. Independent resellers, including Software Recycling LLC, are not endorsed by Microsoft. Their position rests on resale law such as the first-sale doctrine, not on any partnership or approval from Microsoft.

Is Buying Used Software Licenses Legal? US and EU Law Explained

Q: What happens if a used key says it has already been used?

At Software Recycling LLC, if a key fails to activate for any reason, including an already used error, we send a working replacement free of charge and support you until the product is activated. Telephone activation is also supported if online activation fails.

Buying a used, or recycled, Microsoft license is generally lawful in the US and the EU when the license is genuine and the previous owner has stopped using it. The details depend on the law where you are and on the license terms that came with the software. This page explains the main rules in plain language. It is general information, not legal advice. If you have a large purchase or an unusual situation, speak to a lawyer.

What is the first-sale doctrine?

The first-sale doctrine says that once a copyright owner sells a lawfully made copy, the owner of that copy may sell or give it away without asking permission. It is written into US law at 17 U.S.C. section 109.

The doctrine is why you can resell a book, a DVD or a boxed game you bought. Resellers of pre-owned software apply the same idea: a business bought a genuine license, no longer needs it, and passes it on. The original owner stops using the software, and the buyer becomes the only user.

The doctrine does not let anyone make extra copies or sell the same license twice. It covers the transfer of a particular copy, not duplication.

Is software sold or licensed? Vernor v. Autodesk

US courts have asked whether a software buyer owns a copy at all, or only holds a license to use it. That question decides whether the first-sale doctrine applies.

The leading case is Vernor v. Autodesk, decided by the US Court of Appeals for the Ninth Circuit in 2010. Timothy Vernor bought used copies of AutoCAD from a company that had been using them and resold them on eBay. The court held that the company had been a licensee, not an owner, because Autodesk's agreement:

Said that the user was granted a license.
Significantly restricted the user's ability to transfer the software.
Imposed notable use restrictions.

Because the company did not own the copies, it could not pass ownership to Vernor, and the first-sale defense failed.

Vernor is binding only within the Ninth Circuit, and it turned on Autodesk's specific agreement. It shows why the license terms of each product matter. A license that expressly allows transfer is in a very different position from one that forbids it.

How the EU treats used software: UsedSoft v Oracle

In the EU, the Court of Justice ruled in UsedSoft v Oracle (case C-128/11, 2012) that used software licenses can be resold. The court found that when a copyright holder supplies a copy of a program, including by download, in return for a fee and with a right to use it for an unlimited period, its distribution right in that copy is exhausted.

The ruling came with conditions:

The license must be perpetual and paid for, not a subscription.
The original owner must make their own copy unusable when they sell it.
A volume license covering many users cannot be split up and sold piece by piece beyond what the original license allows.

This ruling applies in EU member states. It is not US law, but it shows that a major court has accepted resale of used software in principle.

How license type affects resale

Microsoft sells licenses through different channels, and each has its own terms. Retail licenses are generally the easiest to move, OEM licenses are tied to the device they first ran on, and volume licenses come with organization agreements. Our guide to retail vs OEM vs volume licenses explains the differences in detail.

Point to check	Why it matters
Perpetual or subscription	Only perpetual licenses can be resold. A subscription such as Microsoft 365 cannot be.
Previous owner stopped using it	A license should have one user at a time.
Genuine Microsoft key	Generated or leaked keys are not licenses at all.
Correct product and version	A key must match the software you install.

What makes a legitimate reseller?

A legitimate reseller sells genuine perpetual licenses, tells you exactly what you are buying, and stands behind activation. Look for these signs:

A named company with a real address and working contact details.
Clear product descriptions: version, edition and what the license covers.
An activation guarantee and a support team you can reach.
No claims of endorsement by Microsoft.
No subscriptions sold as lifetime products.

Software Recycling LLC is based in Rehoboth Beach, Delaware. Every key we sell is a genuine Microsoft product key recycled from businesses that upgraded or closed down. Keys are delivered on screen and by email as soon as payment clears, and they stay in My Account > Orders. Online and telephone activation are both supported. If a key fails to activate, including an "already used" error, we send a working replacement free of charge and support you until the product is activated.

Red flags of fake or misused keys

Most problems with cheap keys come from sellers who are not reselling a genuine license at all. Watch for:

Lifetime Microsoft 365. Microsoft 365 is a subscription. A one-time payment for lifetime access is not a genuine offer.
Activation tools or scripts. You should only ever need a product key and Microsoft's own activation. Anyone asking you to run a third-party activator or KMS emulator is not selling a license.
Remote access requests. A seller who needs to log in to your computer to "activate" it is a risk to your data.
No company details. No business name, address or support channel means nobody to contact when a key stops working.
Keys sold as screenshots or stickers with no record. You should get a key you can keep, along with an order record.
Mismatched products. A key for one edition sold as another, or a volume key sold to a home user without explanation.

Where we stand

Our position is that reselling genuine pre-owned licenses is legal under the first-sale doctrine (17 U.S.C. section 109). We also recognize that courts have examined the license versus sale question, as in Vernor v. Autodesk, and that the outcome can depend on the facts and the license terms. Microsoft does not endorse Software Recycling LLC, and we do not claim that it does.

Once activated, the software receives Microsoft updates and security patches like any other license. If you are planning to buy for a business, our guides on Office 2021 vs Office 2024 vs Microsoft 365 and Windows Server core licensing help you choose the right product.

Need help?

If you have a question about a license before or after you buy, open a ticket at /support, use the contact form, or call +1-888-470-5516. Free tech support is available 7 days a week.