Boy, was I frustrated today......

turned on my mac, and as soon as the login screen appeared my mouse pointer behaved very erratically. No matter what I did, it always jumped to and fro, and put itself mostly in the right lower portion of the screen. If I moved it to the centre, it jumped back.

Tabbed to my login, and entered my password. On the desktop, same behaviour. So I logged in to my trustworthy, always working, never-have-problems Windows box ( ) to google. Found out that there are quite some users having or having had the same problem. Often related to other connected hardware, like Firewire drives.

I connected/disconnected all peripherals, and the problem dis-appeared. Then, one by one, I reconnected. Found out that the USB port to the USB hub gave the problem. So connected/disconnected each of the 7 or so usb devices, and I finally found out it was the Wacom tablet that was causing it.

Was about to scrap it, until I noticed my wife had put the stylus, in it's holder, on top of the tablet.. causing the tablet to constantly negotiate mouse position with the stylus..

All in all, took me about an hour to figure it out...