Mouse Acceleration on a Mac – What it is and How to Adjust or Disable it
What is mouse acceleration?
Mouse acceleration is something most Mac users don’t think twice about, many aren’t aware it even exists. By default the mouse drivers count the movement of your mouse and depending on your sensitivity settings, the cursor will then move across the screen by a similar and consistent distance. Mouse acceleration is basically a threshold setting on top of this, so when the mouse is moved past a certain point or at a certain speed, the cursor itself moves more quickly and goes further, thus accelerating the movement speed and rate of the mouse cursor.
How to Disable or Adjust Mouse Acceleration
There are several ways to disable or adjust the mouse acceleration curve in Mac OS X, here are 3 easy ways to turn it off or tweak the curve:
1 – Disable mouse acceleration with defaults
The following defaults write command will disable the mouse acceleration curve in Mac OS X. This is entered into the Terminal once and can be reversed or adjusted by changing the -1 at the end. You generally must log out for the change to take effect:
defaults write .GlobalPreferences com.apple.mouse.scaling -1
Hit return for the mouse scale to change, then log out and in or reboot for it to take effect. You can technically change the scaling number to just about anything you want by adjusting the number on the end.
You can also read the current Mouse Acceleration setting by doing the following command:
defaults read .GlobalPreferences com.apple.mouse.scaling
For most mice in Mac OS X, the default is set to “2” or “3” but some users will find values as low as 0.125 and 0.25, it really depends on what type of mouse you are using and your version of Mac OS X. Thus, if you want to restore to the default setting for mouse acceleration you would use this command:
defaults write .GlobalPreferences com.apple.mouse.scaling 2
You typically need to log out and back in for the change to take effect.
2 – Using a command line script to stop mouse acceleration
Another alternative is a little script written by chrisk called “killmouseaccel”, it runs on a Mac and disables mouse acceleration while it’s running, and a reboot turns it off and on. Learn more about the script to disable Mac OS X mouse acceleration via the command line here.
This easy to use script will completely disable mouse acceleration in Mac OS X. Settings are reversible by rebooting the machine. This is a favorite for Windows gamers.
3 – Manually Adjust Mouse Acceleration with a Preference Panel
For users who want precise control of mouse acceleration on Mac, you can download a free pref panel to enable such a feature. Mouse Acceleration preference pane is here – you can manually adjust or disable the mouse acceleration via this preference pane in Mac OS X, this is handy if you want to manually adjust the curve rather than just disable it.
If you are looking for just instant changes and turning it off, I would recommend the command line methods, if you want precise control over the acceleration curve the preference pane is very useful.
Why do people dislike mouse acceleration?
Many new Mac users aren’t used to mouse acceleration, or the higher curve that Mac OS X’s acceleration provides compared to Windows. Mouse acceleration can cause a loss of cursor precision, particularly when trying to draw with the cursor in certain applications, or more commonly in gaming. The most common mouse acceleration complaints come from the gaming world, where the acceleration curve can lead to unanticipated mouse movements in games like Team Fortress 2 and Starcraft 2, amongst many others.
Personally I don’t mind mouse acceleration at all, but I have used Macs for a long time so the curve does not feel foreign to me. Many Mac switchers from the Windows world come to Mac OS X and find the cursor feels funny and more responsive, these are generally the people who would want to tweak the curve or disable the feature. For the record, mouse acceleration does exist in Windows it’s just at a different threshold and sensitivity.