What version of gThumb is this (check in Help > About)?
It could be that the old importer script is still present somewhere on the system, and it is unmounting the gvfs mounts ("gvfs-mount -u ~/.gvfs/gphoto2*").
Old versions of gThumb (2.10.x) conflicted with the gvfs/gphoto backend, and had to umount those gvfs mounts.
The new versions (2.12.x) are compatible with the gvfs/gphoto backend, and unmounting things would actually be harmful.
So, look for some "helper script" that might be unmounting things.
I don't actually use Ubuntu, so this theory could be all wrong...
What version of gThumb is this (check in Help > About)?
It could be that the old importer script is still present somewhere on the system, and it is unmounting the gvfs mounts ("gvfs-mount -u ~/.gvfs/gphoto2*").
Old versions of gThumb (2.10.x) conflicted with the gvfs/gphoto backend, and had to umount those gvfs mounts.
The new versions (2.12.x) are compatible with the gvfs/gphoto backend, and unmounting things would actually be harmful.
So, look for some "helper script" that might be unmounting things.
I don't actually use Ubuntu, so this theory could be all wrong...
- Mike