Zune is Microsoft's music player hardware and software and associated music subscriptions inaugurated in 2006 and now subsumed under Xbox Music. Zune hardware has been discontinued.

Beyond that problem, Canalys sees trouble brewing between Microsoft and hardware vendors who might license Windows 8 to package with their own laptops and tablets. The analyst firm recommends that PC vendors hold off launching Windows 8 bundled with ARM-based devices - a package known as Windows RT. The firm says the vendors should wait until Microsoft rethinks its high license fee for Windows RT software before they ship these products, but doesn't say how much that fee is. Microsoft hasn't announced what it will charge, but some press reports say it could be $50 to $65 per unit.

Plus the hardware vendors are angry that Microsoft is competing directly against them with Surface and Surface Pro, Canalys says. "Marketing, distributing and servicing such hardware profitably is hard," says Chris Jones, Canalys vice president and principal analyst. "Once the Surface makes a material dent in Microsoft's [profit and loss], it will need to repair relationships with PC vendors, who are already preparing lists of demands."

None of this is going to help Microsoft's declining share of the PC market or the tablet market, Canalys says. If Microsoft hopes Windows 8 tablets will cut into sales it may need to subsidize them, the analyst firm says. That subsidy should be $50 to $100 per tablet just "to kick start the market," Canalys says.

Canalys says that in the second quarter of this year PC sales, which include tablets such as iPads, rose 12% over the same quarter last year, with leading the way with 19.4% of the units shipped. The iPad accounted for much of that lead, the firm says. HP, Lenovo, Acer and Dell followed in that order.