At the end of January, concomitantly with the customer availability of Windows Vista, Microsoft will deliver Windows Live OneCare build 1.5 that has already been released to manufacturing at the beginning of the year.

The initial release of OneCare offers both virus and spyware protection via a single engine. "Indeed, in v1.5 we now have a single "engine," to scan and handle viruses and spyware. This benefits our customers in two distinct ways: first, you no longer need to distinguish between virus and spyware protection, it's all part of the same technology. This is consistent with our mission of keeping it simple - most users have told us they aren't interested in learning the fine distinctions between threat categories. They simply want to be protected, so that's what we are providing," explained Yoav Schwartz, OneCare Lead Program Manager.

While with OneCare v1 Microsoft only delivered an anti-virus, and Defender was necessary to handle spyware, with build 1.5 OneCare has swallowed Defender. The immediate result is that OneCare 1.5 and Defender can no longer coexist as stand-alone applications on the same system.

"If Windows Defender is installed on a machine and then OneCare v1.5 is installed afterward, by default the installation will disable Windows Defender. Windows Defender will then display a dialog indicating that it has been disabled, and asking if the user wants to turn it on again. When you are installing OneCare v1.5 you should close this dialog without re-enabling Defender. OneCare intentionally disables Defender because it can cause system instability to have both running at the same time, and since OneCare is a superset of Defender, there is no reason you would need both of them running," added Schwartz.

In Windows Vista, Defender is an integer part of the operating system and, as such, it cannot be uninstalled; it can only be disabled.