Unresponsive mouse wheel on macOS Sierra Since I upgraded to Sierra, mouse wheel scrolling has become a lot worse. When I scroll the wheel fast, it behaves like it did before and scrolls a bunch of lines, but when I scroll the wheel one notch at a time, nothing happens.

I use a Steelseries Sensei gaming mouse but I also tested with a basic Dell mouse. (There's no model number on it.) As of macOS 10.12.1, this issue affects all programs.

Are there any workarounds? Please don't suggest USB Overdrive or any other nagware.

Edit: I found a video (not me) which shows the issue perfectly. Clearly it's not just me.
I've looked for many solutions and USB Overdrive, is the only one that I've found that fixes it. Would love to hear if there are others, because I agree the nagware aspect is annoying (although it's only on boot, so it's not actually that bad).

Install it, then, in the settings, set "Wheel up" to scroll up "2 lines" and "Wheel down" to scroll down "2 lines". For whatever reason you have to use "2 lines"—"one line" still exhibits the issue. It's possible your mouse will require different settings.