The organisers confirmed that the software giant, which had booked one of the biggest stands at the exhibition, had suddenly changed its mind and would not be exhibiting at the London event.
The show's organiser, IT Events, had previously described the event as the UK's largest enterprise IT event. The company's Web site boasted that: "the biggest names in the industry will present their technologies that are set to redefine enterprise computing."
However, the show, which derived its name from Microsoft's Windows NT platform, appears to have fallen foul of Microsoft's marketing hype.
Simon Moores, chairman of the independent user association, the Microsoft Forum, suggested that Microsoft was angry the show did not reflect the company's current XP and .Net stance.
"It seems that Microsoft is saying Enterprise NT is legacy. But many people run a mixed environment with Windows NT, 2000 and maybe XP," said Moores.
Moores told CW360.com that the software company appeared to be interested only in raising software licence revenue from its new operating systems rather than supporting real world users and third-party IT businesses which, in many cases, have to work with older Windows software.