The man in charge of Microsoft’s latest mobile operating system, which many see as the company’s last chance to stake a claim in the increasingly pivotal smartphone software market, has quit the company.

Windows Phone development manager Charle Kindel wrote on his blog that is was leaving the position to start a new company.

Kindel joined the WIndows Phone team in 2009 as the general manager, driving the effort behind Windows Phone 7, arguably the first successful mobile operating system Microsoft has released. The operating system is carried on phones from LG, HTC and Samsung among others.

Although the OS received good reviews, the lack of some features such as multitasking, a universal search, and unified email inbox was critised by Endgadget. Kindel is leaving Microsoft just before the company releases an updated OS, codenamed Mango, to address these issues.

Kindel was very positive about Windows Phone in his farewell email. "To the Windows Phone team: I may stop using some Microsoft products now that I’m out of here. But not Windows Phone. The BEST product Microsoft has ever built. Do not let up!" he wrote.

Prior to his work on Windows Phone, Kindel was the GM on Microsoft’s Home Server project and worked on a string of Microsoft products including Windows XP, Windows NT and Windows 95.

His new company "has to do with sports, advertising, mobile, social-networking, and, of course, the cloud," he wrote, and has received angel funding.