Since you mentioned in the other thread that you're using Moon+, have you had any problems with Moon+ not reporting itself as an epub or mobi reader? I have the paid Pro version, and it shows up as a pdf reader option in CC, but won't answer calls for other formats.
It's not really essential right now, as I've been importing from within Moon+ anyway, but as I get more content on my tablet, there's a good chance I will prefer to navigate my collection from within CC instead. I've reinstalled both CC and Moon+ Pro, and then rebooted the tablet and resynced, but no joy. I'm just wondering if the issue is specific to me somehow or if it's a limitation of Moon+.