I'm using Shotwell to re-group my large photo collection; version 0.20.2. There are a number of Canon .crw files. If I use the 'camera' developer, every time I rum shotwell it creates hundreds of *embedded.jpg files. Or embedded_1.jpg.. _2.jpg..... If I use the 'Shotwell' developer the same happens but with shotwell_n.jpg files.
How can I prevent this misbehaviour & is it a known bug (not found here or Googling)?