ipad epub transfer solution
I was in a real snit because calibre epubs would not transfer to the ipad. My error was "file missing" every time I tried. Due to other issues I did a full reset of the ipad while connected, and while I lot a lot, I now could download epubs with out issue.
Another suggestion - had 20 gig worth of comics on the thing that I deleted through the app. The app did not see them, but they were still taking up space. Delete everything through itunes.