Microsoft officials admit that Windows 10 cannot meet the ambitious goal of being installed on 1 billion devices by mid-2018.
http://www.notebookcheck.net/Windows-10-will-not-run-on-1-billion-devices-by-mid-2018.169381.0.html
Freudian slip? Your title can be also read as: by mid-2018 1 billion devices won't be able to run Windows 10. Cool.
Matter of perspective, I guess. "Windows 10 will not reach 1 billion devices by mid-2018" could be valid as well. The interesting question that remains is if they will ever get one billion devices running it at all...