Microsoft Skips "9" . . . New Version will be a 10

The logical name for the OS would be Windows 9, but Microsoft jumped to Windows 10 to reflect what it sees as a big break from the past.

“Because we’re not building an incremental product, the new name will be Windows 10,” Terry Myerson, executive vice president of the Operating Systems group, declared at a launch event in San Francisco, where he showed some early code.