I had installed hard drives that were not auto mounting.
I used menu/preferences/disks and the drives were set to use the ‘Automatic mount options’ button but that didn’t mount them
Next I unselected the ‘Automatic’ feature and set things as follows:
- checked mount at startup
- checked show in user interface
- in the space just above ‘Mount Point’ I replaced the default options with:
defaults,errors=remount-ro,x-gvfs-show - I left the others as they were
That worked. Now all my drives/partitions show up mounted.