It seems that almost all of the problems posted here can be traced back to "syncing" problems of one sort or another, the solution is... DON'T SYNC use simple drag-n-drop to load books, use your device to create collections/sort books and access library/stores/dropbox
is your books collection so complicated that you really need "tags" etc ???
THe internal memory can handle 2000+ books ... do you really need an sd card (except for backup)... if you keep it simple it's unlikely you will encounter most of the problems posted here