Comment 10 for bug 802964

It seems that mount icons on the launcher can also be affected once an improper mimeapps.list is created.
On a fresh install 07/17 it can be set straight simply by editing 2 lines in /etc/gnome/defaults.list
inode/directory=
x-directory/normal=
Both use nautilus-folder-handler.desktop which doesn't exist, switching to nautilus.desktop causes that to be set as the default and allows tash and mount icons to open in nautilus
Bug #797000