Juha Christensen, a Danish national, was a cofounder of Symbian, Microsoft's mobile market rival, but he left Symbian to join Microsoft four years ago, where he was responsible for the launch of Windows mobile software products. Christensen will leave Microsoft on December 1, to start his own San Francisco Bay-area mobile devices services company. Christensen's departure, just at the point when mobile devices are gaining in market strength, is seen as a blow to Microsoft's efforts in building relationships with carriers and manufacturers.

"We can't comment on why Juha is leaving Microsoft," observed an IBM spokesperson, "but, with his background at Symbian and the relationships and knowledge he brought to the table, he was extremely important to conveying Microsoft's position to the marketplace. His experience at Symbian helped him understand the needs of carriers and OEMs and his departure leaves a gaping hole in their mobile strategy. Microsoft, by its own nature, is basically a PC company and the software needs in one area don't always translate to the needs in another."

Microsoft expressed regret that Christensen was leaving, but declined to comment on the reason for his departure. "He has brought great understanding of the market and strategic insight into what Microsoft can do to build a great business," said a Microsoft spokesperson.

Christensen had helped Microsoft strengthen its position in the handheld computer business and forge connections with European mobile phone operators Orange, MMO2, and T-Mobile. However, many of the larger phone companies have preferred to utilize Symbian's operating system over Microsoft's.