Menu
To turn off mouse acceleration, simply ensure that “Enhance pointer precision” is not checked. If there's a checkmark visible next to the option, simply click inside the box to remove it and click on the Apply button. You should immediately notice that your mouse movements are behaving differently.
Open System Preferences -> Accessibility. Scroll down to Pointer Control. Click Mouse Options. Disable Inertia.
mouse. scaling -1 disables mouse acceleration but changes the speed.
A lot of my reputation on StackOverflow has come from people voting up this answer, which I wrote way back before I realised that there are several stack exchange websites and that StackOverflow is for programming questions and answers only. Therefore the question above is about how to tackle this if you want to code your own mouse drivers. For all other discussion, go have it here on the superuser site where it belongs.
Original answer follows.
There's a hidden preference that you can change from the Terminal. To read its current value type
defaults read .GlobalPreferences com.apple.mouse.scaling
at the Terminal prompt. Normal values are 0 ~ 3, which can be set by moving the 'Tracking Speed' slider in the Mouse pane of System Preferences. Values of 0 ~ 3 won't disable acceleration, therefore.
However, if you set it to -1 by typing
defaults write .GlobalPreferences com.apple.mouse.scaling -1
in the Terminal, that seems to disable acceleration and set the mouse tracking speed to some constant predefined value which you can't change.
I found I had to log out and back in again for it to take effect. After that, the pixels pointer moves / meters mouse moved ratio is constant but unfortunately not adjustable.
To revert back to Apple default settings, just open the Mouse pane of System Preferences and change the Tracking Speed to anything, then quit System Preferences.
Mac OS X stores mouse and trackpad settings independently. If you want to disable acceleration on a trackpad instead of a mouse, the instructions are the same, just replace with com.apple.trackpad.scaling wherever you see com.apple.mouse.scaling in the above (and use the Trackpad pane of System Preferences instead of the Mouse pane, obviously).
I won't cite a source, since this tip is available in many places on the web. I tried it in OS 10.7 Lion, but many of the sources claim to be using 10.6 Snow Leopard.
If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
Donate Us With