Two years after trying to build a consumer antivirus business, Microsoft has decided to throw in the towel.

The software vendor said Tuesday that it will discontinue retail sales of its Windows Live OneCare product at the end of June next year, and instead offer Windows users free antivirus software, code-named Morro.

Microsoft is phasing out OneCare in order to focus its efforts on getting Windows users to adopt antivirus (AV) technology, said Amy Barzdukas, a senior director of product management with Microsoft. "Our goal with OneCare was to get more customers more protected, and I don't think we were able to do that to the extent that we would have liked," she said.

Nearly half of Windows users don't use AV and in emerging markets that percentage is even higher, she said. "As we look around the world now, the countries where PC growth is most rapid, in emerging markets such as Brazil and India and China, the malware threat is even greater," she said.

Morro is expected to ship by the end of 2009 and online OneCare sales will be gradually phased out sometime after that.

Morro will use the same antimalware engine that is in OneCare and Microsoft's corporate Forefront security products, but it will not be bundled into the operating system, Barzdukas said.

As with OneCare, Morro will have the same kind of antispyware features that are found in Microsoft's Windows Defender.

Designed to appeal to people who have not bought antivirus software, Morro will use less system resources than OneCare. It will also have fewer features. It will protect PCs from malicious programs such as viruses and Trojans, but will not include the systems management and backup capabilities that come with OneCare.

The free antivirus software will be available in the same markets where OneCare is currently sold, Microsoft said. OneCare subscribers will continue to receive support through the end of their subscriptions.

Microsoft shook up the consumer antivirus market when it began selling OneCare in May 2006. Antivirus vendors worried that Microsoft would use its desktop monopoly to push customers to the product, and OneCare itself represented a reinvention of the antivirus category, with its backup and management features and its three-user licensing model.

But the product did not perform well in reviews and ultimately failed to challenge the dominance of antivirus leaders such as Symantec and McAfee.

One antivirus vendor said that a free lightweight AV product from Microsoft was a good idea. "There is so much malcode now that there is a need for more than one AV on any given computer," said Roger Thompson, chief research officer with AVG Technologies, via instant message. "The vendors need to make them lighter on resources, and able to run simultaneously."