Microsoft will not develop a universal code version of its Virtual PC product to run on Intel-powered Mac systems and plans to discontinue the product.

"We will discontinue development of Virtual PC for Mac and we willl not be creating a universal version or a version that will run on the old and new Apple machines," Scott Ericson, Microsoft's director of product management and marketing for the Macintosh business unit, told vnunet.com.

Creating a universal version of the application would take too much effort because of Virtual PC's age, he said.

"We realised that it would essentially be like creating a version one product all over again."

"It's not an apples to apples comparison. You need to start over again and rebuild it."

Programmers are required to create a special version of their applications to make efficient use of the Intel processors in the new systems. Old applications will still run on the Intel Macs through an emulator, but this leads to a significant performance drop.

When Apple announced its switch to Intel processors at its World Wide Developers Conference last year, chief executive Steve Jobs promised an easy transition for programmers.

Microsoft, however, is not the first software developer to balk at the transition costs. Adobe last May said that the version of its Photoshop graphics editing suite could take until April 2007 because of the efforts and costs required for creating the universal code.

Microsoft's Ericson contended that creating universal code might be easy for new applications, but takes a major effort for large applications with a legacy.

"Anything that has been around in legacy, those are not as quick to move over as Jobs may have insinuated."

Users of the Microsoft product are advised to migrate to a new virtualisation platform. Parallels currently offers an OS X virtualization product. VMware later this year will launch a beta of its virtualization product for OS X.

Apple plans to launch its Boot Camp technology as part of OS X 10.5 Leopard in the spring of 2007. The technology is currently available as a public beta.

Microsoft acquired Virtual PC in 2003 when it bought Connectix. It has since used the technology as the foundation for its Virtual Server product.

• A podcast interview with Scott Ericson is available on the Silicon Valley Sleuth blog.