macbook pro not detecting projector I have a MBP that suddenly stopped detecting an external projector. I have used the same laptop with the same projector before. Right now when I boot the same laptop to the Windows partition it works fine with the projector, so I don't think it is a hardware problem. Any suggestions as to what to try? I have tried the "detect displays" trick and that doesn't seem to work.
I would say it's your adaptor. I had the exact same behaviour. Changed the cables over and it started working again. 

I've had it happen on HDMI cable and mini display port/thunderbolt adaptor.