Single click behaves like double click. Mousedown behaves like single click On my macbook, with a mouse plugged in (Microsoft Intellimouse Optical), a single click will sometimes behave like a double click, or pressing the mouse button but not releasing it will behave like a click.  This behavior is sporadic.  Sometimes it will happen with every click for a few clicks.  Sometimes it will be every other click.  Sometimes it behaves normally for a while.

I've been using this mouse with my macbook for weeks without incident until a couple of days ago.  This only happens at home.  I have an identical mouse at work that does not give me any trouble.  I'll work at home with my mouse behaving badly, go to work and have no issues, then come home and the mouse behaves badly again.  At work, my mouse is plugged into a USB hub.  At home, it's plugged directly into the usb port.  I've tried swapping USB ports, but the behavior did not change.  I've tried rebooting.  That didn't help either.

How should I further troubleshoot and resolve this issue?
The misbehaving mouse is surely having hardware issues. This behaviour is very likely not caused by software. Plug in the mouse to another computer to confirm. If the mouse is indeed having hardware issues, you should get it replaced replaced under warranty.