Windows 10 Scroll Wheel Not Working In All Windows

Sigh, guess I should have paid a little more attention. I had KatMouse (http://ehiti.de/katmouse/) installed previously, and that was causing the issue. Leaving this here for anyone who's interested.

Similar to Nick, I had "WizMouse" installed before the upgrade to achieve the "scroll inactive windows" functionality prior to Windows 10. Once I'd upgraded to Windows 10, WizMouse caused the mouse wheel to work on all programs except the Microsoft Metro apps (e.g., Weather, Edge).

Disabling or uninstalling WizMouse in my case fixed it. Hope this helps someone.