Originally Posted by ellisha77ca
What about an epub validator? Can I use one of those to make sure my files are not corrupt, or are they not so reliable?
It's not just whether the book is "corrupt" or not. Some ePubs are perfectly valid, but give the Kobo a hard time due to the complexity of the markup or CSS inside the ePub. These files might validate fine, and work no problem on a PC, but a single book can take the Kobo many, many minutes to process. The O'Reilly ePubs are one notable example, but I'm sure there are others.
Best advice is to definitely load the books in chunks. If you do, say, 500 at a time, keep going until you run into problems. Then remove the last 500 books you added, and add the first 250 of those back on. See if the problem occurs. if so, repeat. Delete the 250 and add the first 125 back on, and so on. Eventually, you'll find the book(s) that are causing problems.