Plan ahead and don't be quick to upgrade large installations, Gartner suggests.

A new research report by Gartner advises customers that they likely won't complete a full migration to Windows Vista until 2008, even though the next version of Microsoft's Windows client OS is scheduled to ship at the end of 2006.

However, Gartner does not advise holding off on Windows Vista upgrades until 2008, as some news outlets have reported, said Michael Silver, research vice president and co-author of the report "Ten Reasons You Should and Shouldn't Care about Microsoft's Windows Vista Client," in an interview Tuesday.

Silver said that if customers wait to adopt Windows Vista until 2008, it will take at least another year before they can fully deploy the operating system throughout their IT environment. Therefore, he said, he does not advise holding off on taking a look at Vista migration until 2008 because it will only delay the completion of the deployment process.

Deployment Takes Planning

It generally takes an organization 12 to 18 months to prepare for a widespread deployment of a new operating system, Silver said.

"If you don't start your testing until 2008, you won't deploy until 2009 or later. If I start testing when Windows Vista ships, I will probably be ready for 2008."

Silver and another Gartner analyst, Neil MacDonald, wrote the research report, which was released last week.

Silver acknowledged that customers running Windows XP have a little more time to upgrade to Vista than those running Windows 2000. Windows XP will continue to be supported by third-party application vendors and Microsoft for some time in the future. However, while companies still running Windows 2000 will have support from Microsoft until 2010, they may not have support for the OS from third-party application vendors that far into the future.

"If you're on Windows XP, you have more runway because you're on an OS that is not only supported by Microsoft but also all the applications vendors," Silver said. With Windows 2000, however, support from other software vendors has already "started to wane," he said.

"Even though Microsoft will give me security fixes until mid 2010, if I have business applications that are more critical, I need to accelerate a move off Windows 2000 at some point," Silver said.

Customer Concerns

Terry Byers, chief technology officer at Teleflora, a Microsoft customer in Los Angeles, said her company, which has about 700 employee desktops, is running on Windows XP Professional Edition and likely will upgrade to Windows Vista after the first cycle of patches to the OS are released.

"We let the product get stable and get some of the patches out of the way and then we do it," she said of her company's typical process for OS upgrades.

Byers added that when Vista comes out, the company likely will first upgrade employees who need to run a series of applications simultaneously on their desktops--such as those in IT or marketing--and then gradually update desktops of the entire company staff.

"It's not unusual for us to run in a mixed mode," she said. "The next time an OS comes out, I'm on it. But it might be three or four months for a lowest-level employee to be on it. We don't have any issues with that at all."

There are several things Microsoft can do to help encourage customers to upgrade to Windows Vista more quickly and efficiently, Gartner's Silver said. The company should not only ensure that two generations of its older products will run on Vista, but also that software vendors will support Vista with both older and current versions of their applications as quickly as possible.

Microsoft also should provide customers with testing tools to ensure that their applications will support Windows Vista, Silver said.