Microsoft says it has fired its chief information officer, Stuart Scott, for "violation of company policies", but declined to give details.
Mr Scott oversaw IT for Microsoft's 80,000 employees
Mr Scott oversaw the use of computers, software and networks by the US software giant's 80,000 employees.
He joined Microsoft in 2005 from General Electric, where he worked for 17 years on various positions.
General manager Shahla Aly and vice president Alain Crozier will assume his duties until a replacement is found.