Originally Posted by Feisty
I don't have nearly that many ebooks so I'm just using the internal memory that the Kobo comes with right now. I did think that maybe I was being impatient (I was trying to load around 5-10 at a time initially) so I tried with just one, regular sized epub. It "Processed Content" for 3 hours before I gave up and restarted it.
I didn't have any issues downloading a book I purchased from the Kobo store tonight. I haven't tried from Calibre again for fear of locking my Kobo up and maybe corrupting data (I factory reset it prior to loading the Kobo book). Seems the issue is just between my reader and Calibre (not saying anything against Calibre, it's a fantastic program).
Sorry after reading the reast of these posts I cant offer a suggestion, except to run a scan disk on your kobo to check for errors. I dont think it will find anything. I susspect its as you suggest a corruption of Calibre.