Microsoft on Tuesday announced that it would retire its $50-a-year security subscription product, Windows Live OneCare, and replace it with a free solution codenamed "Morro." Unlike OneCare, however, Morro will focus only on core anti-malware features and not a broader set of PC maintenance functionality.

"Customers around the world have told us that they need comprehensive, ongoing protection from new and existing threats, and we take that concern seriously," says Microsoft senior director of product management Amy Barzdukas. "This new, no-cost offering will give us the ability to protect an even greater number of consumers, especially in markets where the growth of new PC purchases is outpaced only by the growth of malware."

Microsoft says that Morro will address the most common concerns about today's PC security solutions. That is, it will be free, lightweight and non-resource-intensive, and will work automatically. That said, it will still be based on the same core anti-malware engine that drives OneCare and the company's other client and server security products. This technology has won some important industry awards, but it has fared poorly in other tests as well.

Morro will also dispense with OneCare's non-security features, which include such things as online photo backup, local hard drive backup, and PC optimization tools. Microsoft says it wants to keep Morro as small and light as possible, but it's unclear if the company plans to offer these and other OneCare features elsewhere going forward.

Customers can still continue to purchase OneCare through mid-2009, and Microsoft says it will support the product going forward. Morro is currently slated for a late 2009 release.