Some additional investigation!
For the NAS mount there does not seem to be any issue for the Cubox-i4Pro in my case.
For a USB drive directly connected to the Cubox-i4Pro I find quite a different outcome. First the Cubox-i4Pro may not have enough power to operate the drive directly from the USB port and that results in no mount. If the drive requires less power than the USB port can supply or a powered USB hub is used, then the external USB HDD will mount. To see if it is mounted try this from having ssh to the Cubox-i.
fdisk -l
My result is:
root@volumio:~# fdisk -l
Disk /dev/mmcblk0: 15.7 GB, 15719727104 bytes
22 heads, 16 sectors/track, 87223 cylinders, total 30702592 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x125dde26
Device Boot Start End Blocks Id System
/dev/mmcblk0p1 2048 4194303 2096128 83 Linux
Disk /dev/sda: 1000.2 GB, 1000204886016 bytes
255 heads, 63 sectors/track, 121601 cylinders, total 1953525168 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000000
Device Boot Start End Blocks Id System
/dev/sda1 2 1953525167 976762583 b W95 FAT32
Once the mount is confirmed. I go to the Volumio WebUI Library and update the MPD Database. This takes a few minutes as my NAS music library is quite large. At the conclusion of the MPD Database update I Browse to NAS, WEBRADIO, RAMPLAY, and USB. If I click on USB it opens an empty page. It seems to be empty, but I do have music on the USB drive. I can not access it. Is this a permissions issue or what? The drive is formatted FAT32 as you see from the “frisk -l” output.
I had not previously attempted this configuration, but thanks to your encouragement I now seem to be among friends with similar problems.