There's even fewer reasons for businesses to upgrade to Windows Vista than there were for upgrading to Windows XP, according to an expert in software migration.

Rich Bentley, client and mobile manager for software developer Altiris, also attacked some market researchers for over-optimistic forecasts, in particular Gartner and IDC figures, which suggest that Vista could be in mainstream use by the end of 2007.

The IDC report in particular was funded by Microsoft, he said, adding: "I'd take it with a large grain of salt. And Gartner says that Vista migration starts with 12 to 18 months of preparation - so customers were already planning for it in early 2006? I don't think so!"

Speaking Tuesday in Vienna, where Altiris is holding its European partner and customer conference, Bentley said that a much more likely timeframe is one to two years for organisations merely to start deploying Vista.

He said that the issues organisations face with Vista migration include the need to minimise downtime and preserve user data and settings, the amount of IT time needed to do the work, and of course hardware compatibility. Even machines bought in the last two years may not have the graphics hardware needed for the full Vista GUI, he added, noting though that the software could still be used without that.

Also at the conference, Altiris announced upgrades to its Windows migration software, including support for Vista imaging and deployment, 64-bit software and hardware, and VMware deployment. It has also integrated its software virtualisation system, SVS, with its helpdesk software, allowing damaged applications to be reset remotely and new software to be installed on request.

Bentley claimed that automating Vista deployment via tools such as Altiris could cut the time needed to migrate to one-quarter, but added that organisations could still find when they look into it that it was not worth doing yet. "I don't think there's as many reasons to migrate as there were with XP, so we look at it as something that's going to take place over the next three years at least," he said.

An Altiris user agreed that Vista was not even on his medium-term agenda. Tony Longhurst, the general manager of IT technical architecture at Eurostar, said his company had only just completed its migration to Windows XP. He said that when Eurostar started that process in late-2004, "We saw we weren't the only ones just starting with XP. We've just gone through two years of an incredible amount of work, so we won't be an early adopter of Vista."

Bentley added that Altiris is to publish a free e-book on Vista migration in ten chapters. However, it will be published one chapter a month, starting next month, so readers won't have a complete copy until August 2007.