I'd like to switch the accessibility preference "Scroll with inertia" on and off for a Magic trackpad. The preference can be found in the accessibility preferences/Mouse and Trackpad/Trackpad Options/Scrolling "with/without inertia" (see here: http://de.tinypic.com/view.php?pic=2rw00wg&s=6#.U_NrJrx_ulA).

I think, that this preference resembles the key "TrackpadMomentumScroll" in either the com.apple.AppleMultitouchTrackpad or com.apple.driver.AppleBluetoothMultitouch.trackpad domain.

Using the defaults command doesn't seem to change the preference. At least, OS X doesn't react to the command and the preference in the GUI isn't reacting either.

I guess, I need to restart some daemon to apply the change.

Can somebody help me here?


Kind regards Dennis

1 Answer 1


Oh, found it. You'll have to reload the appropriate kernel extension like this:

defaults write com.apple.driver.AppleBluetoothMultitouch.trackpad TrackpadMomentumScroll -bool false

sudo bash -c "kextunload /System/Library/Extensions/AppleBluetoothMultitouch.kext; kextload /System/Library/Extensions/AppleBluetoothMultitouch.kext"

After that your trackpad will shortly become unavailable, but will be reconnected and have the MomentumScroll setting.

This still isn't, what the System Settings-App does, because you'll have to enter your password for sudo (and be an administrator), but still it works.

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