Vista Service Pack 1 has incompatibility issues

Worryingly for an update meant to improve security subsystems, Microsoft has confirmed that its automated Service Pack 1 update has ‘compatibility issues' with anti-virus software such as Trend Micro Internet Security 2008, Zone Alarm Security Suite 7.1, and Bit Defender's AV and Internet Security.

The update, released to Microsoft Equipment Manufacturers on February 4th with plans for it to be made freely available in March, blocks these programs from starting, leaving computers open to hackers, spyware and viruses.

Microsoft Support, admitting that "programs... are known to experience a loss of functionality when they are run on a Windows Vista SP1-based computer" has published a list of the affected programs , along with links to their homepages where customers should be able to download individual fixes.

Vista Service Pack 1 was originally expected for Autumn 2007, but was delayed due to separate compatibility issues.