A Windows key for 15 euros. Office for under 30. Sounds too good to be legal? Here's the thing: it can be completely legal. But it can also turn into an expensive fiasco. The difference lies not in the price, but in what's known as the chain of rights.
The European Court of Justice and the German Federal Court of Justice have made it clear in several rulings: reselling used software is permitted. Period. But this permission comes with conditions that many dealers simply ignore. And this is exactly where the wheat is separated from the chaff.
What the ECJ Actually Decided in 2012
I keep reading that "used software is now legal." That's not entirely accurate. In the case of Oracle v. UsedSoft (C-128/11), the ECJ ruled that the principle of exhaustion also applies to downloads. This means: once Microsoft has sold a license within the EU, that license may be resold.
But here comes the part that many people overlook: the reseller must render their own copy unusable. They must be able to prove where the license came from. And they must demonstrate that it was originally sold within the EU with the consent of the rights holder.
A key from China or Russia? Not exhausted. A key from the volume license agreement of a company that has gone bankrupt? Legally complicated. A key flogged on eBay without documentation? Roulette.
Why Microsoft Clauses Don't Restrict You
Do you know those passages in the license terms? "This software may not be resold" or "Valid for the first user only"? In Germany, such clauses are largely ineffective.
The Federal Court of Justice clarified this as far back as 2000 (I ZR 244/97). Microsoft had tried to prevent the isolated sale of OEM software. The court essentially said: the distribution right is exhausted. Whatever Microsoft agreed contractually with the OEM partner does not concern the end customer.
It's like buying a car. The manufacturer cannot prohibit you from selling your used car just because some dealer contract states that this is not desired. That's relevant between the manufacturer and the dealer, not between you and the next buyer.
The Invisible Difference: Retail, OEM, Volume
Technically, a key works regardless of where it comes from. You enter it, Windows or Office activates, done. But behind the scenes there are three completely different license types.
Retail keys are what you buy as a private individual in a store or online. You can transfer them to a new PC. They are flexible.
OEM keys are tied to hardware. Dell, HP or Lenovo install them at the factory. Since Windows 8, this key is even embedded directly in the motherboard's firmware. The legal status when reselling is settled in Germany: OEM may be unbundled as well.
Volume keys (MAK or KMS) are intended for businesses. One key for 100 or 1,000 installations. And this is precisely where the problem lies with most cheap offers.
The Truth About 5-Euro Keys
I hate to put it this bluntly, but: a Windows key for 5 euros is, with 99 percent probability, a volume key being resold illegally.
The scheme works like this: a dealer buys access to a MAK key (Multiple Activation Key) that was originally issued for a company. This key has an activation limit, let's say 500 activations. The dealer sells the same key to 2,000 people. The first 500 buyers are lucky, the key works. Then the limit is reached, Microsoft blocks the key, and all the other buyers are left out in the cold.
I've seen error messages like 0xC004C008 ("activation limit reached") myself. Then you're sitting there with your cheap key unable to do anything with it. The dealer? Long gone or no longer responding.
How to Recognize a Reputable Key
The chain of rights is the key. Literally. A reputable dealer can document for you where the license came from. They can prove that the previous owner deleted the software. They don't sell you a volume license as an individual, but genuine retail or unbundled OEM licenses.
My experience shows: the price alone tells you little. A key for 30 euros can be clean, one for 50 euros can be junk. What matters is the dealer's transparency.
Ask:
- Where did the license originally come from?
- Is there a declaration of destruction from the previous owner?
- Is it a single license or a volume key?
- Is there proof of the first sale within the EU?
If all you get to these questions are evasive answers, you know enough.
What the Rulings Really Mean for You
Many people think: as long as the key works, I'm on the safe side. That's wrong. A successful activation proves absolutely nothing about the legality of your license.
The Federal Court of Justice has emphasized repeatedly (among others in the UsedSoft II and III decisions) that the burden of proof lies with the buyer. If you use software and cannot demonstrate a complete chain of rights, you are, strictly speaking, committing a copyright infringement. Even if your Windows dutifully displays "activated" every morning.
For private individuals, the risk is manageable. Microsoft won't be knocking on your door. But for businesses? That's a different story.
The Audit Nightmare for Businesses
Imagine you run the IT department of a mid-sized company. You bought 50 Windows licenses from a cheap online dealer. Saved 3,000 euros. Everything runs fine.
Then comes the Microsoft audit. The auditor finds out that your keys belong to a MAK originally assigned to a university in Poland. No documentation, no chain of rights, no declaration of destruction.
Consequence: 50 PCs are deemed unlicensed. Re-licensing at full price. Plus a 25 percent penalty surcharge. Plus the costs of supporting the audit. The 3,000 euros saved quickly turn into 15,000 euros in additional costs.
It surprised me when I first heard of such cases. But it happens regularly.
How to Check for Yourself What You Have
Windows has a built-in tool called slmgr.vbs. Open the Command Prompt as administrator and type:
slmgr /dli
This shows you the license channel. What you want to see: "RETAIL channel" or "OEM_DM channel." What you don't want to see: "VOLUME_KMSCLIENT" or "VOLUME_MAK."
If yours says "VOLUME" and you're not a business with a volume license agreement, you have a problem. Not today, maybe not tomorrow, but at some point.
The Gray Market Is Grayer Than You Think
I'm no moralizer. I understand that nobody wants to pay 150 euros for Windows when there are alternatives. But the difference between "cheap" and "dubious" is real.
A reputable dealer in used software earns their money with volume and service, not with shady mass keys. They can explain to you where their licenses come from. They give you the assurance that, in case of doubt, you won't be left empty-handed.
A 5-euro key from an anonymous seller gives you nothing but a temporary activation screen and a risk you can't see.
What Ultimately Matters
The legal situation is clear: used software may be sold in Germany. The ECJ and the Federal Court of Justice have confirmed this repeatedly. But not every key labeled "used" is also legal.
The difference lies in the documentation, the origin and the transparency. A dealer who cannot or will not answer these questions is not selling you security. They're selling you a gamble.
And honestly: when it comes to software licenses, gambling is a bad idea. Not because Microsoft will sue you. But because at some point you'll be stuck with a non-functioning activation and no one will want to take responsibility anymore.
The few euros difference between a reputable provider and the cheapest key on the market? That's your insurance. Not against Microsoft. But against dealers who vanish the moment your key gives up the ghost.
