[GeoffR]

I don't know if a reset will help, or if 10,000 ebooks is just too many for the device to handle. I still have less than 1,000 on my Glo, and I only have one shelf (non-fiction) and it contains just a handful of books, so I don't use calibre to manage shelves.

One thing to be careful of with fanfiction, or other books where you might load updated versions of an existing book with an altered internal structure (such as extra chapters or different TOC arrangement), is to make sure you delete the old version from the device before loading an updated version. If you use Calibre to load the new version over the top of the old one then the database doesn't get updated properly, and all sorts of strange things can happen including crashes when navigating the book.

As meeera said, viewing the book in Calibre is not a good way to check for faults in the book, as it will just ignore many errors that can be fatal on other devices. Better to use EpubCheck.

KePub books seem to use a lot more space in the database than ePub, so if there is a limit to the number of books then that limit might be lower for KePub books.


If you do go ahead with a factory reset and reload all your books there are some things you might try:

Just for interest's sake, take a note of the database size before you do the reset. Compare it with the size after you have re-loaded all your books.

Check the save template in the KoboTouch plugin, a reset and reload is the ideal time if you want to make a change. The default template will result in very long pathnames, and create one directory per author. FAT filesystems have limits on the number of files per directory, and long filenames reduce the number of files that can fit. Every extra 11 characters in the filename counts as one extra file towards the limit. Cover and thumbnail images, annotations files, etc. are created using the same base filename so they will be very long too. Also in some situations having lots of files (or subdirectories) in one directory can slow down access, so idealy you want the filenames to be as short as possible, but not result in too many files (or subdirectories) per directory. The template must generate unique names though, so you need to allow for books by different authors with the same title. I don't really know how much effect this has on performance since I don't have a control device to compare with, maybe none, but it can't hurt.

If you don't already then you might want to enable the Upload covers for books option in Calibre's KoboTouch driver. This will save the device the time it takes to generate thumbnails for the first time.