The popularity of mobile devices both at work and at home has had a significant impact on Microsoft’s OS sales — and Windows 8 won’t be a fix for that lost market share, according to a Forrester report published today. “Windows 8 will simply stop the shrinking,” writes Frank Gillett, the author of the report, in a blog post. 

Forrester projects that Microsoft will still own nearly 90% of the PC market in 2016, and 27% of the tablet market by 2016 — but only 14% of smartphone sales. 

2013 will be a year of transition, but Windows 8 will take off in 2014. It is just the first step in an ongoing transformation for the product, according to the report, “Windows: The Next Five Years.” Because Microsoft can’t continue with its three- to five-year development cycle for Windows, Forrester expects a Windows 9 release in 2014. Forrester also believes Office is in development for the iPad, and, to remain relevant in world where mobile devices outnumber PCs at least 2 to 1, the Office team will have to figure out ways to be accessible on Android smartphones and proprietary Android tablets.

The report takes an in-depth look at the future of the Windows brand and forecasts market share for Microsoft — and other vendors such as Apple and Google — in the PC, smartphone, and tablet markets.