I am running a thunderbolt drive where I render most of my videos directly out of. When I went to show pix4d where the image folder was none of the external drives show up. I ended up just running it off the smaller internal drive and it works fine but I would like to have all my files on the external.
We could not reproduce the issue you are reporting. Could you please give us more information on your Mac device and the OS?
It is when you click add directory none of the external hard drives appear. If i click add images all of the hard drives show up just fine.
Can confirm this problem still exists. I have a Mac Pro running High Sierra with ~10TB attached as SAS RAID. The file browser is native but the directory chooser is a non-native dialog view that presents the root file system but none of the mounted external drives. Drag & drop into this non-native dialog box also does not work at all.