Microsoft has blamed Windows giveaways and pirates plundering subscriptions for its decision to cut back the number of Windows activation keys it issues.

The company told The Reg on Wednesday that its TechNet Subscriptions, Microsoft Partner Network (MPN), Microsoft Developer Network (MSDN), Software Assurance (SA) and Open Licensing programs along with promotional giveaways at events and through direct marketing that all offer discounted or free products in exchange for activation codes had all been exploited by prates in the last few months.

In response, Microsoft is cutting the number of keys it issues to unlock the virgin software.

A Microsoft spokesperson told us: “Over the past few months, pirates have exploited these programs and systems to obtain free or lower cost genuine product and have then resold at significant profit margins, depriving Microsoft and its partners of legitimate revenue and leaving users with an improperly licensed and unsupported product.

“Significantly lower prices have helped to undermine channel integrity and drive additional corruption. These changes help us mitigate piracy while helping us serve of legitimate customers."

The change emerged after Microsoft blogger Ed Bott reported here that TechNet Professional subscribers will only be entitled to three product activation keys from later this month, down from five. According to Bott, Microsoft’s TechNet site said:

The allotted keys may only be used for software evaluation purposes. Once the maximum keys have been activated, no more keys will be made available. Additional product keys may be acquired through the purchase of an additional subscription.

He provided a link to the TechNet site but the wording is nowhere to be found. Bott told The Reg the wording is available once you sign in to TechNet but we're still waiting to hear back from Microsoft.

Further, Bott notes, the number of keys allowed in a 24-hour period is being restricted. A TechNet Professional (Retail) subscriber will get 44 keys in that time period.

Microsoft was unable to explain why the change in policy had apparently been removed from the TechNet page.

It’s the latest cut thanks to illegal activation and copying of its code. Microsoft has slashed the number of keys available to TechNet Professional in half in September 2010 – to five from 10. Microsoft had said then that it was trying to cut down on piracy of its software. ®