I use an external usb mouse/keyboard when I use my Mac (and have been for some time without any problems). Since the C-Error 10.12.4 update, my Macbook Pro no longer allows me to set/save my Mouse Tracking Speed in the System Preferences and the mouse tracking speed is stuck on slowest speed.
When I open System Preferences, the mouse tracking speed slider is on ‘Slow’. For a moment after I pull the slider to a higher speed, the mouse speeds up but then immediately returns to the slowest speed, though the slider stays where I set it.
The slider stays at my setting until I exit the System Preferences, whilst the mouse moves as though it's set to the slowest speed. When I return to the System Preferences, after closing it, the mouse tracking speed slider is back to the ‘Slow’ setting.
Moving the slider again repeats what I described above.
I have tried using defaults write -g com.apple.mouse.scaling 8 but that has no effect after logging out and back in. Using defaults read -g -g com.apple.mouse.scaling returns 2 initially, and after I set the speed to fast, it shows 3 on subsequent reads. I have also reset NVRAM but to no avail. However, resetting NVRAM had the, undesired, effect of wiping my UEFI boot settings and now I can't boot into my Ubuntu partition. (Not very happy at the moment!)
The interesting thing is that while my Mac is on the login screen, the mouse tracks exactly how I want it (perhaps too fast since I've been playing with the settings).
Is there any other command I can issue in the terminal to get my mouse working the way I like it and how it was before this latest update?
Best Answer
I ran into this problem this morning. After trying several things which themselves did not work I finally found the solution:
Uninstall SmoothMouse
The app is no longer supported by the developers and they recommend removing it.
You might need to restart afterwards but that fixed it for me.