Comment # 2 on bug 926862 from Dominique Leuenberger

A properly set gdb breakpoint shows that shotwell is hanging, waiting for
libusb to return.

libusb is indirectly linked in by means of libgphoto (addind Marcus to CC)

as a workaround (thus of course loosing the capability to import photos from
USB Cameras directly) is to: rpm -e --nodeps libusb-1_0-0

In this case, shotwell is starting up properly again and regains UI
functionality