In article < XXXX@XXXXX.COM >,
Why are you asking about that in a programming newsgroup? Your message
belongs in comp.sys.mac.hardware.misc and comp.sys.mac.system.
If it's a non-optical mouse, open it and clean the ball & rollers. If that
doesn't fix it, go ask in the right newsgroups, and give more details about
the model of Mac, type of mouse, etc.