The survey of 302 IT chiefs at European businesses also found that 20 percent areup to two years after Vista's corporate release, scheduled for the end of November, before introducing it. Just 6 percent said they planned to deploy within the first six months, and 18 percent within a year.
"This is behind the anticipated rate of adoption in North America, reflecting greater resistance to the Microsoft product strategy from users in the European market," Forrester said in its report.
More than a third (35 percent) of Windows-based PCs in the organizations surveyed still run either Windows 2000 or an older version of the operating system, the research firm found.
The "State of Enterprise Infrastructure 2006" study said that while the overall outlook for IT spending in 2006 remains "austere," enterprises are making significant new investments in hardware, with servers and PCs taking up around one-sixth of the entire IT budget.
More than half (55 percent) of European organizations run Hewlett-Packard servers, followed by 32 percent with IBM servers, 26 percent with Dell, 8 percent with Sun Microsystems and 7 percent with Fujitsu-Siemens. The majority of organizations also only use one vendor, and two-thirds said they are unlikely to change their supplier in the next two years.
But businesses are continuing to struggle with complexity in their server environments; 52 percent of organizations are reducing the number and variety of their server configurations as a priority, Forrester said.
This is leading to more interest in server virtualization, with more than a quarter of organizations either looking at it or already piloting it, the report noted.
In terms of infrastructure projects, disaster recovery and security are the main priorities for the next 12 months, and are driving much of the increased hardware spending, the IT chiefs told Forrester.
Andy McCue reported for Silicon.com from London.