Microsoft has cancelled its autumn Professional Developers Conference, citing bad timing in light of the launch of important infrastructure and platform products.

Microsoft dropped the bombshell about PDC, which was to be held in October in Los Angeles, in a posting on its Microsoft Developer Network (MSDN) site.

"As the PDC is the definitive developer event focused on the future of the Microsoft platform, we try to align it to be in front of major platform milestones," the company said in the post.

However, Microsoft already will have its key new platform technologies - including Windows Server 2008; the next major release of SQL Server; the next release of its Visual Studio toolset, code-named Orcas; and the new Silverlight technology - available before the show. Microsoft said it wants developers to focus on those in the near term.

The PDC is usually held every other year and is timed to give developers an early look at new releases of some of Microsoft's most strategic software products. For example, at the last PDC, held in 2005, developers got an early look at the new Microsoft Expression toolset for building rich internet applications, which was only released last month. However, Microsoft has cancelled the PDC in the past if it didn't think it had the right products to show developers at the event.

One Microsoft partner who often speaks at the company's developer conferences said the move seems to make sense.

"Microsoft's reasoning for this, essentially, is that between MIX, TechEd Orlando and Barcelona, and (I suspect) its Business Intelligence Conference held two weeks ago - and a slew of recent and soon-to-come alpha and beta releases - developers have enough to chew on for a while," Andrew Brust, chief, new technology for consulting firm Twentysix New York, said in a post on his blog. "If my memory serves me correctly, Microsoft made the same decision two PDCs back and, with hindsight, people appreciated the decision and judged it wise."

TechEd Orlando is scheduled for 4 June, while TechEd Developer is planned for November in Barcelona.

Microsoft said it would update the MSDN site when it has set a new date for the PDC. In the meantime, the company is highlighting other developer events it plans to hold in the last several months of the year as substitutes for the "deep, technical training" developers get at the PDC. Those events are VSLive! in New York in September, VSLive! in Las Vegas in October; DevConnections in Las Vegas in November; and TechEd Developer.

One analyst suspects there may be another reason for the sudden cancellation of the PDC. Greg DeMichillie, with Directions on Microsoft, thinks Microsoft may have wanted to show developers an as-yet unannounced-technology at the show, but realised it would not be ready in time. Claiming the show is not timed for software such as Windows Server 2008 may just be an excuse, he said.

"The explanation they're giving is that it's not really timed right for Longhorn, but you know what - that was patently obvious six months ago when they scheduled it," DeMichillie said. "The cancellation could be just that they couldn't get their act together on what it is they want to say."

DeMichillie acknowledged that the timing of the conference is likely difficult for Microsoft to plan, because the company wants developers to have forthcoming technologies available early enough for them to have time to give feedback, but in a mature enough form that Microsoft's plans for the products "have a likelihood of succeeding."

Microsoft may have also decided to push back the conference in an effort to continue its focus on Vista, which was released in late January and is still in its earliest stages of deployment among business and enterprise customers.

"There is a concerted effort there to focus on deploying Vista and I think they're afraid that a big early platform roll-out in the fourth quarter really runs the risk of distracting people," DeMichillie said.

Nancy Gohring in Seattle contributed to this story.