Mouse Acceleration Howto

Tips, tricks and general discussion.



The mouse acceleration prefpane works quite well. But it would be nice to have the possibility to set the overall mouse speed and the acceleration curve independently,
Currently I use 0.1 for my mouse. So this is smallest possible acceleration. The problem is, that the mouse cursor moves quite slow, even if i move the mouse very fast.

Note, with version 1.0 and Leopard, there is a problem with missing semicolons in the localization .strings files which causes the following console error to be generated over and over by System Preferences and Spotlight:

4/12/10 12:25:11 PM System Preferences[237] CFPropertyListCreateFromXMLData(): Old-style plist parser: missing semicolon in dictionary.

Here's the description of the proper format:

Thanks Art! I fixed both downloads.

Hi, Setting the mouse acceleration to 0 produces the results i was looking for in case of acceleration. But the movement is to slow then. Going back to the native Mouse-Pref-Pane to make it faster turns acceleration back on.

Am I doing something wrong?

The IntelliPoint drivers from Microsoft are a solution – MICROSOFT MOUSE – It really works for me! I bought the same one as author of this article (Microsoft Arc Mouse):

Thank you so much!

Thanks a lot, i listen to so many music files a day and this app helped me A LOT. I use Snow leopard.

This is almost what I was looking for... Changing it to -6 does seem to make it LINEAR (without acceleration) but it moves way too slow.

I hate how if I move slow the cursor moves to a crawl. Hopefully a newer version will fix this.

Perhaps -24...

Anyone know what the best settings are in 1.1 to make the mac cursor feel like windows? BTW thanks for writing this program, wish apple would finally fix it in OS!

Hi guys if your irritated by the mac mouse acceleration too, then please sign this Petition. We need a change this problem and apple needs to know that!!

Thank you and let us hope ^ ^

Hey I've been checking your site since: Mon, 2010-03-08 10:34. Which you've gotta admit, is a long time, and there still isn't a fix for the auto start bug in 10.6, I really do appreciate that you do this in your own time and I'm in no way trying to sound ungrateful. But please fix this issue! it drives me crazy having to re-enable your prefpane settings every time I turn on my mac.



Steve, I don't know about a fix for startup on 10.6. I don't remember any bug report. Mail me some details and I'll get on this.

Just to jog your memory, if you read down this comment list, you wrote:
Autostart on Snow Leopard
Submitted by zany on Mon, 2010-03-08 13:34.
It seems the autostart feature does not apply on Snow Leopard. I'm looking into it!
The details:
- When the computer boots, I see the prefpane momentarily load into the dock and disappear, and the mouse accel hasn't changed. I then go into the prefpane and manually change the settings which works. autostart box is ticked.
- also, if I change the accel setting to quickly after boot, when the HDD is still accessing after startup, the accel will change back to default after a few seconds. But if I wait till the computer has fully loaded, with no hdd access going on, it will apply and stay applied.

Thanks for looking into it!

There are new downloads now, release 1.0c for 10.4 + 10.5 and release 1.1c for 10.6.
A small bug regarding unicode text in login items which could block the pref pane from running has been fixed.

thanks alot, this works (ive tried usboverdrive, intellimouse-driver, steermouse, nothing was satisfying)!

just for curiousity: is there a way to uninstall the mousefix and the preferance pane? sorry if thats a dumb question, but im all new to osx.

chris, uninstalling is easy: the whole package is contained in one "file". It's located at ~/Library/PreferencePanes/MouseAcceleration.prefPane -- just delete it in Finder.

Downloaded 1.1 and installed it on 10.5. Now I'm trying to uninstall it. However I can't seem to find the file MouseAcceleration.prefPane in that location. Neither does spotlight. Am I missing something? :)

The PrefPane is located either at "Your User" / Library / PreferencesPanes or (if you installed for all users) "Your HD" / Library / PreferencesPanes. It's called "Mouse Acceleration.PrefPane" (maybe without the space). It's the same for every PrefPane on your system.

-1x is perfect for acceleration but to much speed for mouse movement. There´s no different in velocity with -0.1x

Can you put other scroll to adjust it?

Sorry Gn0m4, it's not possible to have different settings for speed and acceleration. There is only one setting in the Apple API.

what are the default values for mouse and trackpad on version 1.1?

Apples default values seem to be 2.0 on both Mouse and Trackpad.

seems to me that the default value for the trackpad is actually 1.0.
2.0 seems intolerably fast.


is there a bugfix for the autostartup yet? i got this bug with your current version on OSX 10.6.3 with a magic mouse.
If you have no time to fix it, could you please point me to the used API so i can fix it myself?

thanks in advance

This does nothing - it's just a duplicate of what the standard mouse tracking speed does!? Am I missing something here?? I still have an annoyingly uncontrollable mouse action with this application set to run at login.

If I set it to 1.0x the mouse is unusably slow (OS X Mouse Tracking speed is at the furthest left position)
If I set this to 1.2x the mouse is unusably fast (OS X Mouse Tracking speed is at the 4th position from the far right)
If I set this to 1.1x the mouse feels exactly the same as it did before I installed it and funnily enough...OS X Mouse Tracking speed is at the 4th position from the far left, which is exactly the same position as I used to have it set at...and still annoying!

It seems to me that this pref just takes the 10 increments of the standard mouse tracking that is built into OS X and turns it into 4 increments! (Far left, far right and 4 from each end!) :-/

Please note that the settings allow for negative values. Those settings reduce the acceleration for most people.

I have been trying out Mouse Acceleration v1.0 on Tiger and have been comparing it to another FREE program MouseZoom.

Mouse Acceleration has much better graphics. But if I change the acceleration settings using the Apple Pref Pane, the new value does NOT show up in Mouse Acceleration Pref Pane. It shows the wrong value.

This behaviour does not happen with MouseZoom. i.e. If I change the acceleration settings using the Apple Pref Pane, the new value DOES show up in the MouseZoom Pref Pane.

It would be great if you could make Mouse Acceleration check and display the right acceleration value.

Thanks Rob K. Your suggestion makes a good point. I'll add some code to check the current value set from the built-in Pref Pane.

How do you reset this to default values?

The Default value should be 1.0 or 2.0. You can also use the build in mouse speed pref pane. To set a value.

No, you can't, apparently OS X' built-in mouse speed pref pane overrides accel pref pane and vice versa, due to Apple's decision to merge speed and acceleration. Try to set the mouse speed most left and THEN an accel like -1.0x. Then try to set an accel like -1.0x andthe mouse speed most right. You will get the exact same result.
I was looking forward to trying this pref pane but couldn't find a value that felt natural. Maybe someone did find one? I'm using a Magic Mouse on a 22" screen.

boy ... i wish someone smart could fix xp's acceleration which was broken right under everyones noses

I'm trying to get Apple to change their minds on this. It worries me that they've removed the acceleration API call.

Hi. This tool is great! I have it set to -0.4x and that works perfectly for me, however it doesn't seem to be working at login. The mouse speed goes extremely slow, and I have to go into preference and just click on the slider and it all works. I note that 1.1c was supposed to fix something like this? I have downloaded the latest version, but nothing is better ('get info' shows files version as 1.1 not 1.1c is that right?). Also, it always switches to 32 bit when opening in pref pane - sis that right? I am on latest build of Snow Leopard. Cheers.

A true 64-bit version needs very different code for the preference pane. At the moment I'd rather keep the backwards compatibility to 10.5 and 10.4.

I'm still investigating why the setting resets at startup.

I would like to slow down the mouse, so that moving the mouse 10 meters in real space only reaches across the screen. To be able to paint on the screen while dancing.
Is that possible?

Slowing the mouse down to only once across the screen while moving the mouse 10 meters in real space won't be easy with the current API. Setting a custom acceleration curve might do the trick (The curves can slow down arbitrarily as long as each movement results in at least one pixel).
Contact me by mail Kjell!

I have a Universal Access question. I need the cursor larger to see well, which I can do easily within the preference pane, but it has always annoyed me that the resolution of the cursor's enlargement is awful. It is very hard for me to find any information regarding this and I cannot even find the file location of the cursor image. Any help would be appreciated.

I haven't worked with Cursor Zooming yet. I guess you could replace the used image with a custom one. I can't point you to the icon file without digging into the resource files though.

Thanks Zany! This tool is great. Unfortunately, the changes I make in the pref pane don't go into effect at startup... I may have to resort back to Jonathan's "crude excutable." Any progress on that front?

Also, it's kind of annoying to have to restart the entire pref pane just to run yours, is that some kind of 64bit issue? Thanks again!

Did you resolve this problem? I have same, after system restart I have to setup from the beggining, it's really annoying :/

Sadyl on every boot up, it looses the setting on 10.6 :(

I finally solved the problem with unset acceleration on restart. Get the new download (version 1.1 d).

Hi there. To everyone who's got that problem - easy to fix it. [b]You need to go to[/b] [color=blue]~Library/Preferences[/color] and [b]find and delete[/b] this file: [color=blue]org.zuckschwerdt.MouseAcceleration.prefpanel.plist[/color]
It sholud reset preferences and help you. Thanks :-)

You sure you can't disable acceleration in snow leapord? Have you seen this project:

More info from :

Mousefix And Snow Leopard

Mousefix does not work with Snow Leopard. The reason is that the API that Mousefix uses (see 'Bugs' above) has now been removed as of the Snow Leopard release. If anyone would like to try and modify Mousefix to work with Snow Leopard, then it is the call to 'NXSetMouseScaling' that is causing problems. This has now been replaced with a similar function called (I believe) IOHIDSetMouseAcceleration. I do not run Snow Leopard and am very unlikely to do so, so I am afraid I can't help any further in trying to fix this issue, but my understanding is that the new function is not as good as the old one in the control that it provides, so any modification to Mousefix may not result in a satisfactory fix. Anyway, good luck to anyone out there that fancies giving it a go.

Zack, the old functionality of NXSetMouseScaling was already disabled in 10.5 Leopard. The API was marked deprecated and later removed with 10.6 Snow Leopard. The only thing left is setting the speed and with a small hack (negative speed settings) you can counter acceleration. My project now is about setting the acceleration with precise detail to match other common OS. Its two parts: parameterizing the stock driver (more natural curves) and hacking the driver (sub-pixel precision matching other OS). The first part is done, the second still WIP.

I have to say that I don't think I'd be able to keep my Mac if it wasn't for this fantastic fix. Here's one suggestion though:

As an Autocad user, I have had the problem of accidentally triggering zooming in/out when panning across model space. To fix this, I found another great pref pane app called Magic Prefs, which lets me have greater control (and even app-specific control) of multi-touch on the magic mouse and trackpad. It does a lot of great things, however it still does'nt fix the acceleration curve. When I use these two apps (Magic Prefs & Mouse Acceleration) in tandem though, it works fantastically. The only issue that I have, is the following:

1. When I open the control panel to edit the MP prefs, it overrides MA. After I finish editing, I can then open MA, click the speed ticker where I want it to be, and MA will take over again. Only a minor inconvenience, but still an annoying one.

2. When my iMac goes into sleep mode, then awakens, MA is disabled again (I'm assuming the MP process gets kicks in after MA, causing the same issue as #1).

I really can't live without BOTH of these wonderful tweaks. It would be great if they could either be combined into a single preference pane, or made to at least work together (with MA overriding the MP tracking setting).

The upcoming Mouse Curve app will track changes to the speed setting (by other apps, sleep/wake, …) and restore custom value.

Thank you, thank you, thank you!
I have been frustrated with this issue to no end and this fixed it. It's not exactly perfect, but I can finally get the mouse pointer to go where I want it to. I am using 10.6 Snow Leopard and even with the limited options I got a setting that works for me. I am on a macbook pro 13' so these settings may not work for those on a larger screen. I set the mouse accelerator to -2.3x and set the mouse tracking to the fourth setting from the left. Also, for programs that have mouse settings, like games, turning down the mouse speed seems to help. As I said, its not perfect, but it makes my computer usable.

I cant find any type of related file in the preferencepanes folder and i dont know how to uninstall the app along with the settings it has changed, how do i do this?

Open ~/Library/PreferencePanes
Remove Mouse Acceleration.prefPane

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