I'm wondering if you should hook up the nook on a powered USB port - if it's on a non-powered hub. If you are direct to the computer that should work. It's possible it can't mount the device because it's corrupt but that's unlikely.

I'd restart the Mac (yeah it's a windows thing ... ) and the nookColor just to get to a known good state.

When it is plugged in and working clicking the "eject" icon in finder next to the nook would be the way to eject it.

I had same proplem with my iMac; After nearly an hour with friendly and earnest help desk consultant and no luck, I just decided to reboot the Mac...Problem solved, ColorNook recognized.

I hope this helps.

I used my macbook from 5 years,but now-a-days i had little problems in my macbook and i'm so much worried about this.My Nook Color will not mount on my MacBook. It did on a first attempt, but now will not. I've tried rebooting the computer and the nook. The USB cable does not seem to make a stable connection at the nook. Do I need a new cable? Any suggestions would be appreciate.
Having the same issue!! It seemed like it did connect at first, but now, it does not show up at all on my macbook as an external hardrive