Microsoft Windows users are finally starting to move in numbers from XP to Vista, according to analyst Forrester Research.

The firm surveyed 962 IT decision-makers at North American and European companies, and found that Vista deployments could "dethrone XP as the operating system of choice in the enterprise."

Forrester's study shows Vista running on nearly 10 per cent of North American and European corporate desktop systems. But when asked about plans to roll out Vista, a third of those surveyed said they had already started, with 26 per cent citing plans to deploy this year or later.

the initial analyst recommendations on Vista deployments were that organisations would wait until service pack 1 was released, but the issues Microsoft had with Vista's perceived problems with application and driver compatibility appears to have pushed major deployments closer to the release of service pack 2 (SP2).

However, SP2's release to manufacture, appears to have slipped to late in the first half of the year, with speculation rising that Microsoft was trying to give would-be deployers another reason to move to Vista, before releasing its next operating system, Windows 7.

Forrester reported that enterprise interest in Apple's Mac OS X had also increased markedly, even if it only accounts for three per cent of the market.

"Over the past three months, we've fielded an increased number of client enquiries on the impact [of Apple] on the client and the consumerisation of IT's effect on client management and client security processes and technologies," said Forrester's report.

Other findings from the survey are that, XP still powers 71 per cent of PCs within North American and European enterprises, Windows 2000 is now limited to 10 per cent of enterprise PCs, and Linux adoption is flat at two per cent.