"I downloaded it via Windows Update, and got a bluescreen on the third part of the update," wrote "Iggy33" in a comment posted Wednesday on Microsoft's Vista team blog.
Iggy33 was just one of dozens of posters complaining about Vista Service Pack 1's effect on their PCs. "What a disaster," wrote "SeppDietrich" of the update. "It exiled all my Nvidia drivers to the Bermuda Triangle."
"Bikkja" said that "after installing SP1 things seem to go really slow, even though my computer shouldn't have any problems."
Other troubles reported by Vista SP1 users ranged from a simple inability to download the software from Microsoft's Windows Update site to sudden spikes in memory usage. "Went from using 650 MB RAM idle to 1 Gig... I'll be switching back," said "Kurrier."
It's not uncommon for major software patches to cause problems when first released. Windows XP Service Pack 1 inflicted numerous glitches on host computers when it shipped in 2002. Microsoft fixed many of the problems with subsequent patches.
Microsoft on Tuesday made Vista SP1 widely available for the first time. The company has admitted it's still not perfect.
The service pack will not install on computers that use peripheral device drivers that Microsoft has deemed incompatible. The list includes a small set of audio and display drivers made by Realtek and Intel, as well as drivers from several other manufacturers.
Microsoft said it's working to resolve the compatibility issues.
Computer users with Vista already installed on their systems can now download Vista Service Pack 1 for free from the Windows Update site. Some retailers, including Amazon.com, are offering boxed versions of Vista SP1 for sale starting Wednesday.
The software is available in five languages: English, French, German, Japanese, and Spanish.
Vista SP1 contains numerous features designed to enhance the operating system's speed, performance, and stability. Among other things, it offers a patch that will allow users to run the BitLocker encryption tool on multiple hard drives. It also improves the speed at which the OS wakes up from hibernate mode.
SP1 will also remove from Vista the so-called Kill Switch -- a feature that deactivated key components of the OS if Microsoft detected users were not running a properly licensed copy of Vista.
The feature was plagued by false alarms that flagged thousands of legitimate Vista users as software pirates.
All told, Vista SP1 includes more than 300 hot fixes for the OS.
Users will need to install three prerequisite files onto their computers before they can upgrade to Vista SP1. Those files are also available through Windows Update.
Microsoft is hoping that Windows Vista SP1 will quell some of the disappointment that greeted the operating system's initial rollout early last year. Many corporate and home users complained about its resource requirements and lack of compatibility with existing applications.