Mac OS X laptops have a system preference setting to disable the touchpad mouse when an external mouse device is connected.[link|http://www.intellitools.com/techsupport/faq/IntelliKeys%20USB/ikusb_12mtrackpad.php|http://www.intellito...b_12mtrackpad.php]
From under the Blue apple icon, select System Preferences. Then open the Keyboard & Mouse icon. Deselect "Ignore trackpad when mouse is present."
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