The head of Microsoft's $15bn (£9.6m) Servers and Tools business, Bob Muglia, will leave the company this year after 23 years service.
Muglia's departure from the unit, which sits at the epicentre of Microsoft's cloud strategy and is behind its Azure platform, came by mutual agreement with CEO Steve Ballmer.
In an email sent to Microsoft staff, Ballmer said: "Bob Muglia and I have been talking about the overall business and what is needed to accelerate our growth. In this context, I have decided that now is the time to put new leadership in place for STB."
"This is simply recognition that all businesses go through cycles and need new and different talent to manage through those cycles," he added.
During his time at Microsoft, Muglia has overseen the firm's Developer, Office, and Mobile Devices Divisions, among other things. He was handed control of the Server unit in 2009.
Microsoft has lost a number of senior execs in recent months, including CFO Chris Liddell, software head Ray Ozzie and Office boss Stephen Elop, who is now running Nokia.