SAN FRANCISCO  That didn’t take long.

Just 48 days after Microsoft began selling the Kin, a smartphone for the younger set, the company discontinued it because of disappointing sales.

The swift turnabout for the Kin, which Microsoft took two years to develop and whose release was backed with a hefty ad budget, is the latest sign of disarray for Microsoft’s recently reorganized consumer product unit.

“It’s an absolute failure,” said Charles S. Golvin, an analyst with Forrester Research. Mr. Golvin said he was surprised to see Microsoft kill a product so quickly, given the company’s history of sticking with new products and improving them over time.

Microsoft’s consumer products unit has struggled to offer a credible competitors to Apple’s iPod and more recently the iPhone and an array of smartphones powered by Google’s Android software.