Comment # 1 on bug 957055 from Martin Glora

Some testing led me to gvfs, which was not working.

"Caught in the dependency-hell" ;-)

Upgrade to sane-backends-1.0.25 last week also caused an upgrade of my
favourite photo program shotwell. Upgraded version didn't work, thus I decided
to downgrade shotwell once more which conflicted with the newly installed 
libgphoto2_port.so.12.0.0. Getting out of this dilemma I seem to have
uninstalled gvfs-backends.

The following packages were installed:
gvfs-backend-afc
gvfs-fuse
gvfs

Uninstalling and reinstalling led to a conflict for gvfs-backends. After
installing gvfs-backends mounting of usbs and cds worked fine again.