Microsoft officials denied that the US Department of Transportation's recent snub on Windows Vista means the whole government is reluctant to install the new operating system.

In a report that was circulated internally within the department by DOT chief information officer Daniel Mintz in late January, that only surfaced publicly on 5 March, the IT manager placed an indefinite halt on upgrading to Vista.

Mintz, in his memo, questioned both the new OS's compatibility with other programs, including earlier versions of Windows, and the estimated cost of moving to Vista.

Despite the setback, Microsoft executives claim that Vista adoption is moving forward at a consistent pace in government, and on par with similar installations in the private sector.

Although aware of the budgetary and scheduling conflicts that often cause the federal government to lag behind businesses in bringing on board major new technologies, Microsoft contends that the OS is already finding a home in the sector.

"We're wrapping up the largest early adoption program for the Windows OS ever, and over ten percent of our partners were from the federal government," said Patrick Svenburg, Windows client solution specialist with the Microsoft Federal group. "This also represented our largest partnership ever with the federal government; we worked closely with them throughout the entire development cycle to address their concerns and priorities."

Svenburg said that Microsoft is planning to host senior officials from the DOT in Redmond before the end of March to address the concerns the department expects to encounter in moving to the OS.

In his memo, Mintz specifically cited "lack of a compelling business case" as a reason for temporarily banning Vista, along with Microsoft Office 2007 and the Internet Explorer 7 browser.

To be fair, Mintz and other DOT officials attributed some of their reluctance to upgrade on the agency's planned move to a new Washington headquarters later this year.

The DOT technology executive didn't immediately respond to calls seeking further comment.

Microsoft representatives said that like many of its largest, Enterprise Agreement-level customers, government organisations such as the DOT will need to use the software maker's compatibility and deployment automation programs to help overcome some of the perceived challenges with Vista deployment.

Some industry watchers believe, however, that it may still be hard for many federal agencies to make a sufficient business case for spending the time and money needed to move to the new OS.

Specifically, most of the major departments have invested heavily in moving their critical applications to web-based systems, which could dampen enthusiasm and demand for Vista and Office, said Shawn McCarthy, a government IT analyst with IDC.

"A lot of government sites have been trying to migrate more applications to web interfaces that any desktop system can access, and that's taken pressure off the organisations on the client side," McCarthy said. "The individual agencies are under a lot of pressure to make a business case any time they want to do systems upgrades; if they can't really justify with benefit that will be seen, the upgrade either doesn't happen or migration is slower."

The analyst said that despite Microsoft's claims that features such as improved security will convince government CIOs to get behind Vista, federal decision-makers will take a wait-and-see attitude and delay upgrading until the operating system's advantages are proven by others.

Other experts said that it's too early to pass judgement on government or private-sector adoption of Vista since large organisations don't typically move to new technologies quickly.

Michael Cherry, analyst with independent research firm Directions On Microsoft, said that the Transportation Department and other agencies will likely move to Vista incrementally over time.

Organisations will also need to spend valuable time and money doing extensive evaluations of the OS before any installation begins, which could push back adoption further, he said.

"When I read the [DOT] memo, I heard an IT department asking its people to refrain from buying ad hoc Vista licenses and machines, because they can't support that yet," said Cherry. "Something else to consider is that IT people have a lot of projects that they're already working and limited resources; Vista is not the kind of thing that merits dropping everything else to move on it quickly."

Cherry said that he does believe federal agencies will begin adopting the OS at the same rate that they retire older desktop systems, although he noted that IT departments will likely give more consideration than ever before to alternatives including open source and Apple products.

The first types of government users the analyst believes are likely to install Vista for functional reasons will be employees who carry sensitive data on their laptops, or view such information remotely on their PCs, he said. Those users will be seeking the on-board protection offered by the BitLocker encryption feature of Vista, Cherry said.

In general he believes it's too soon for anyone to worry about adoption of the new OS.

"It's way too soon to be taking individual cases or data points and trying to make a trend of them," Cherry said. "Vista might be good, but it's not so good people are going to dump their existing machines overnight just to get it."