Mac users who attempt to boot Microsoft's Windows Vista operating system on their computers by using a new version of Apple's Boot Camp partitioning software may encounter some problems, Apple has conceded.

In a posting on its Web site, Apple warns users of its Mac Pro systems that Boot Camp 1.2 may not be able to launch Windows Vista as designed without a workaround in cases where the Microsoft operating system has been installed on a secondary drive.

To get around the problem, Mac Pro users wishing to use Windows Vista on their Mac OS X-based machines first need to employ the Boot Camp Assistant software to create a dedicated Windows partition on the secondary drive and then start the Windows Vista installation process as usual.

If the installation routine hangs, users need to shut off their Macs and then "physically disconnect the internal drive that is the Mac OS X startup drive," according to the posting. They then need to restart the computer and continue the installation process.

Apple released Boot Camp 1.2 last month. The software, still in beta, is supposed to allow users of Intel-based Macs to launch Windows Vista trouble free. To date, however, Apple has had difficulty updating its products to work properly on the new Microsoft operating system, which was released to consumers at the end of January.

Apple's iTunes music player software, for instance, still suffers problems on Windows Vista despite a recent patch from Apple that eliminated some glitches. Among the problems yet to be fixed: Ejecting an Apple iPod from a PC by using Vista's "Safely Eject Hardware" feature may result in corruption of the iPod.

Apple says users need to be sure to select the "Eject iPod" button from within iTunes to disconnect their iPods from Vista PCs.