The leader of Microsoft Business Solutions (MBS) Doug Burgum has unexpectedly announced he will leave the company at the end of June next year.

Burgum's position of senior vice president of MBS will be immediately taken over by the current head of research for MBS, Satya Nadella, although Burgum will remain on in his current role for the next nine months to help Nadella transition into the role.

In November 2005, Burgum and Jeff Raikes, president of the Microsoft Business Division, announced they were looking for a successor for Burgum, who joined the company when Microsoft acquired Great Plains Software in April 2001 and has been instrumental in reshaping the company's ERP and CRM business. At the time Burgum said his intention would be to remain at the company as chairman of MBS.

Last week, another high-lying Microsoft exec, Brian Valentine, announced he was leaving to join Amazon.

On a conference call yesterday, Burgum said he decided to leave the company last week after talking with Raikes in part because he lives in North Dakota, and has no plans to move to Microsoft's headquarters in Redmond, Washington. "I have personal constraints relative to geography," Burgum said. "I always felt this was a job that needs to be done full time in Redmond and not by someone who is commuting."

Burgum said he has given "little or no thought" to what he will do once he leaves Microsoft, and that for now his focus is on "driving the MBS business moving forward."

While Microsoft originally said the search for Burgum's successor would be an external one, Raikes said the company ultimately choose Nadella after reviewing external candidates because he is "the best person for the job."

Nadella has been with Microsoft since 1992, and he joined the MBS unit in 2001. Prior to his current position, he led the global development team for Microsoft's Dynamics.