caja unable to mount HDD

Hi, I have Ubuntu MATE 16.04 installed on an SSD. I also have a HDD which comes up at unmouted by default which is fine (I want that). The problem is that when I click on the HDD device in Caja a dialog box comes up saying it can't mount it - at least mostly, sometimes it works. I then have to go into the Control Center -> Disks utility and mount it, which works fine.

A related problem is that USB sticks gets mounted by default when I insert them, I don't want that. I generally only want to get stuff mounted when I click on the device in Caja. The automatic mounting in Caja of USB sticks is flaky anyway, sometimes it says that it couldn't mount them even though it did.

The main problem is the failure to mount the HDD. The HDD is a data drive containing my music formatted as ext4.