[sirmaru]

Personally, I would uninstall Calibre, remove all Calibre folders and use Regedit to remove all references to Calibre in the software sections of the Registry.

Then unregister your Sony eReader from the Sony store.

Then do the same with Sony's Desktop reader.

Then ONLY do a clean install of Sony Desktop Reader 3.1 and get an ID and password from the Adobe site. You will need the latter to properly install your Sony eReader and register it at the Sony store.

After all of this open the Sony Desktop Reader 3.1 and only then plug in your eReader from Sony.

Sony is developed ONLY for Sony. They make no provisions for Calibre compatibility.