[NiLuJe]

@stevebw: Unlikely to be caused by the (plugin) update, it was comprised only of fairly trivial changes that are nowhere near the processing code.

Check the output in a shell (i.e., run calibre through calibre-debug -g), my guess is something's wonky with the metadata cache. 4K books on a K3 is bound to be slow without a cache, and even with a cold cache, or even validating it might be long, especially if the USB connection gets wonky...