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Deactivate your Sudden Motion Sensor on your Apple portable

There are a number of reasons users may wish to deactivate their Sudden Motion Senor technology in their Mac portables.

Joe Aimonetti MacFixIt Editor
Joe is a seasoned Mac veteran with years of experience on the platform. He reports on Macs, iPods, iPhones and anything else Apple sells. He even has worked in Apple retail stores. He's also a creative professional who knows how to use a Mac to get the job done.
Joe Aimonetti
2 min read
There are a number of reasons users may wish to deactivate their Sudden Motion Senor technology in their Mac portables. Environments where extreme vibrations and movement occur frequently, such as live performance venues, can inadvertently trigger the Sudden Motion technology in your Mac and cause interrupted sound or video playback as the hard drive heads are required to park.

The Sudden Motion Sensor is built-in to protect your hard drive in the event that your computer is dropped while functioning. While this technology has been available in Apple notebooks since the PowerBook G4 and is constantly being fine tuned, there are some instances when users may want to disable it. Please note that disabling this feature leaves your hard drive at greater risk should you drop your Mac.

Disabling the Sudden Motion Sensor:

  1. Open Terminal (Applications > Utilities) and enter:
    sudo pmset -g
    Press Return.
  2. Enter your Administrator password when prompted and press Return. This command will let you know what the current setting is for the Sudden Motion Sensor (the default is "1" for on).
  3. In Mac OS X 10.4 and greater, in your Terminal window, enter:
    sudo pmset -a sms 0
    Press Return and enter your Administrator password when prompted. This will disable the Sudden Motion Sensor. You can enter the (sudo pmset -g) command to check the setting.

These changes to the Sudden Motion Sensor settings will remain in affect even after restarting your Mac. To re-enable the Sudden Motion Sensor, open Terminal and enter:

sudo pmset -a sms 1
Press Return and enter your Administrator password when prompted.


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