Good day,
I have tried goggling and have not found what's causing the problem. Sometimes Calibre recognizes the nook color and the SD card within it and sometimes it doesn't. Yesterday I was putting things on all afternoon and to make sure everything looked right I disconnected and reconnected a couple of times and calibre kept recognizing it just fine.
Today it's not recognizing it, I've tried disconnecting it and reconnecting with calibre open,calibre closed, connecting it while in sleep mode and then turning it on while connected to the computer and having it already awake when I connected it in case that made a difference.
I have tried restarting the computer and running the repair calibre options.

any ideas?