Windows 10 (pro, enterprise, any) that supposedly have never been activated so far are (re) sold online for 5$-20$. I assume that those are key that have initially been given out by microsoft in volumes or in countries with lower pricing (as the price is around 200$ when bought directly from microsoft).

Is it legal to resell Windows license keys? Are there any kinds of Windows 10 pro/enterprise keys for which it is forbidden to resell them?

  • Key generators are common for most software out there, and Windows is no exception - the key is NOT an indication of a valid license, its only indication of a valid key. Microsoft requires a valid license and a valid key, only having the latter of the two does not make you legal. People selling keys for cheap are 99.999% of the time not selling you a legal license.
    – user28517
    Apr 5, 2020 at 3:25
  • Similar to Resellers of Windows OEM licenses
    – Eliezer
    Jan 26, 2023 at 18:26

3 Answers 3


In the EU, software license resale is legal, even if explicitly forbidden by terms of any EULA or other contract imposed upon the parties. To quote the European Court of Justice's press release on its ruling in a case in Germany between Oracle and a German reseller,

An author of software cannot oppose the resale of his `used' licences allowing the use of his programs downloaded from the internet. [...] The principle of exhaustion of the distribution right applies not only where the copyright holder markets copies of his software on a material medium (CD-ROM or DVD) but also where he distributes them by means of downloads from his website.

Where the copyright holder makes available to his customer a copy – tangible or intangible – and at the same time concludes, in return form payment of a fee, a licence agreement granting the customer the right to use that copy for an unlimited period, that rightholder sells the copy to the customer and thus exhausts his exclusive distribution right. Such a transaction involves a transfer of the right of ownership of the copy. Therefore, even if the license agreement prohibits a further transfer, the rightholder can no longer oppose the resale of that copy.

There are many such companies in the EU who resell software legally, including used OEM Windows licenses that are far cheaper than retail copies. This is, in my opinion, a fantastic thing -- but undoubtedly has been behind the trend towards time-limited licenses rather than perpetual ones, which we all arguably suffer from today.

  • 1
    Does this mean that you could transfer one time or subscription purchases of apps from mobile app stores from one account to another and that Apple must allow and facilitate this? Jan 21, 2023 at 21:36

Under Kirtsaeng v. John Wiley & Sons, a copyrighted work, sold with permission from the rightsholder, may be resold in the United States regardless of where the copy was originally sold, without the consent of the rightsholder. This means that authorized copies of Windows, originally sold outside the United States, may be resold in the US by anyone in lawful possession of them. This assumes, however, that:

  • The entire boxed copy is sold as a physical unit. While I tend to expect that reselling a key is likely to be lawful as well, I'm not aware of any case law specifically covering this scenario, and we've seen 17 USC 1201 used and abused to achieve a variety of strange results in the past. It is much harder to argue that selling an entire box could violate that law.
  • The installation media was lawfully obtained. If someone purports to resell one of Microsoft's volume-license keys, that is probably a violation of their agreement with Microsoft (volume-license keys are not normally sold to consumers), and it is likely to infringe copyright in some way as well (volume-license keys can be used to activate more than one copy of Windows, and are normally used by large organizations to simplify IT operations - since the same key can authorize multiple activations, it might violate the exclusive right of reproduction).
  • No further copies have been made, and in particular, the installation media has not been used to install Windows on any computer (even without activation). The resale might still be legal if the seller deletes all copies of Windows prior to selling the installation media, and/or sells the copies with the original pursuant to 17 USC 117 (such copies may not be sold separately), but I'm not aware of a lot of case law on that, and the EULA might affect the seller's obligations here.
    • OEM keys are a bit of a gray area here. By the time the consumer obtains the key, Windows has already been activated for that device. Trying to separate Windows from the device might be a §1201 violation (see link above). See Apple v. Psystar.
  • Any relevant customs duties are paid, if applicable, and the transaction does not otherwise violate US embargos or trade policy.

If someone offers to sell you a designer handbag for $25 you can pretty much bet that you are dealing with the gray market or the black market. Same for bargain software keys. Computer manufacturers make deals with Microsoft allowing them to distribute copies of Microsoft software as a bundle with the computers they sell. They aren't allowed to resell the software without the computer. Sometimes employees or outsiders get access to the activation keys allocated to the company, and then re-sell them on warez sites. Microsoft also makes licenses available to vendors at cheaper rates in some countries, but the contract with Microsoft will forbid the resale in countries not covered by the agreement.

Laws for software licensing, copyright, and intellectual property differ widely from country to country. In the US this would almost certainly be a violation of the Digital Millennium Copyright Act and subject to criminal prosecution.

In most countries it would at least be a violation of the licensing terms and addressable by a civil suit by Microsoft.

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