Originally Posted by Chrysanthemum
And if nothing happens in Calibre when I connect the PRS-300, then what? Because nothing happened. When I connect the Nook, it's recognized. But not the Sony. And I have tried them separately.
If your OS sees it and mounts it as a USB drive then it will work.
Unplug your charging apple device (iphone) and then it will see your 300 fine.
If you aren't going to use your apple device as an ereader you can go to Preferences - Plugins - Device interface plugin - disable the Apple device interface plugin.