Microsoft has released the long-awaited first Windows Vista Service Pack, a wrap-up of incremental updates that apparently cripples certain vendors' software.

SP1 tackles reliability and performance, adds support for new hardware and wraps in earlier updates for compatibility with third party software. Microsoft claims more than 2,000 applications are now "certified for" or "work with" Windows Vista.

The only problem? A number of security products won't start up or run on updated desktops thanks to "compatibility problems". Among those affected are BitDefender AV or Internet Security, Fujitsu Shock Sensor and Zone Alarm Security Suite. Meanwhile, other products will experience "loss of functionality" once you've installed SP1, Microsoft said.

Microsoft has also introduced a number of security changes to Windows Vista, including updates to BitLocker drive encryption. And SP1 is "aligned" with Windows Server 2008, the two operating systems sharing common files in Internet Information Services and concurrent user support.

The first Windows Vista SP has long been seen by some analysts, at least, as the catalyst for broad uptake of the operating system among businesses. SP1 can be downloaded here.®