Microsoft is warning customers that the soon-to-be released service pack for its Windows Vista operating system won't fix the application capability issues that have plagued the software since its release in January.

"Applications that have compatibility issues with Windows Vista today will most likely continue to have the same issues with Windows Vista with SP1," Microsoft warns in a new whitepaper on Vista Service Pack 1.

As a result, Microsoft says businesses needn't bother waiting for SP1's final release -- slated for early next year -- to test new applications on Vista, because the results won't change much.

"Microsoft recommends that all enterprise customers begin testing their applications on the currently available version of Windows Vista," the company said.

Many users were likely hoping for more.

Industry surveys and anecdotal evidence have shown that many businesses have shied away from Vista due to concerns about application compatibility and resource requirements.

The problem: updating applications for Vista is much more complex than revising them for the move from Windows NT and ME to XP that occurred in 2001.

The biggest challenge, according to independent software vendors and Microsoft, is getting apps to work with Vista's advanced security features, such as the User Account Control. It's designed to prevent desktop users from making changes to their system images without approval from an IT administrator. The feature operates at the kernel level and can affect the way third-party applications, including antivirus software, work.

In its whitepaper, Microsoft concedes that "the changes made in the Windows Vista release that enhance security, reliability and networking that might cause earlier versions of applications to break are being carried forward in Windows Vista SP1."

The upside, according to Microsoft, is that all applications that currently run properly on Windows Vista will continue to work on Vista SP1.

The final version of Windows Vista SP1 is expected to be released in the first quarter of 2008. A release candidate is currently available as a download.