Microsoft KB Archive/149228

= How to Disable Mouse Acceleration =

Article ID: 149228

Article Last Modified on 11/1/2006

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APPLIES TO


 * Microsoft Windows NT Advanced Server 3.1
 * Microsoft Windows NT Workstation 3.1
 * Microsoft Windows NT Advanced Server 3.1
 * Microsoft Windows NT Workstation 3.5
 * Microsoft Windows NT Workstation 3.51
 * Microsoft Windows NT Server 3.5
 * Microsoft Windows NT Server 3.51

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This article was previously published under Q149228



SUMMARY
The default settings for the mouse have acceleration enabled. To disable acceleration in the Mouse Control Panel tool, you can move the Mouse Speed slide bar all the way to the left. However, this makes the mouse pointer move very slowly in relation to the movement of the mouse. Disabling acceleration is desirable for some users of Windows NT, such as CAD users, but making the default mouse speed the only speed is impractical.



MORE INFORMATION
To calculate the mouse speed under Windows NT, three settings are used: Mouse Speed, MouseThreshold1, and MouseThreshold2.

Mouse Speed sets the relationship between mouse and cursor movement when the value of either MouseThreshold1 or MouseThreshold2 is exceeded. When this occurs, cursor movement accelerates according to the value of MouseSpeed.

MouseThreshold1 and MouseThreshold2 set the maximum number of pixels the mouse can move between mouse interrupts before the system alters the relationship between mouse and cursor movement. If the mouse movement exceeds the threshold defined by MouseThreshold1 and if MouseSpeed is greater than 0, the system moves the cursor at twice the normal speed. If the mouse movement exceeds the threshold defined by MouseThreshold2 and if MouseSpeed is 2, the system moves the cursor at four times the normal speed.

Using the slide bar in the Mouse Control Panel tool, you cannot disable acceleration without making the mouse pointer respond very slowly to the mouse movements. It is possible to overcome this limitation by manually setting the MouseThreshold settings so low that any movement at all is accelerated. Mouse pointer speed will no longer increase factorially with an increase in mouse movement, but still moves at a rate higher than normal.

WARNING: Using Registry Editor incorrectly can cause serious, system- wide problems that may require you to reinstall Windows NT to correct them. Microsoft cannot guarantee that any problems resulting from the use of Registry Editor can be solved. Use this tool at your own risk.

To implement a higher default mouse pointer speed for the currently logged in user, use the Registry Editor (Regedt32.exe) to edit the following registry key:


 * 1) Set the value of MouseThreshold1 to 0.
 * 2) Set the value of MouseThreshold2 to 0.
 * 3) Set the value of MouseSpeed to 1 or 2 (1 doubles the normal speed, 2 quadruples the normal speed).
 * 4) Close Registry Editor, close all applications, and restart Windows NT.

Additional query words: prodnt mice

Keywords: kbusage KB149228

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