MacBook not detecting external display I have an old MacBook 1.1 and since I upgraded to Mac OS X 10.6 it does not seem to connect to my external Monitor or TV. I'm using the Mini-DVI to VGA adapter. I've tried using detect displays and made sure the monitor is outputting through VGA. 

The strange thing is I have my MacBook set up to dual boot into Ubuntu and I can use the external monitor when in Ubuntu. It seems to be software issue on the Mac OS X side. 

Can anyone suggest any troubleshooting steps?
Try resetting the PRAM:
http://support.apple.com/kb/ht1379