It shouldn’t be necescary to do all that command line stuff.
Some of that will mess up Volumio’s OTA updating.
You should just be able to use your FAT32 formatted USB drive as it is on your Mac and Volumio. Most external/portable USB drive come formatted FAT32 as far as I’m aware.
Mmm, that’s the constant one, this line is in allmost all pi-manuals on ‘how to connect externall hdd’, so now I got even more confused. My initial idea was to have the disk in fat32 and the vfat command, untill I found the hdfplus remarks. But fat32 should be OK.
BR
Paul
p.s. what about the controlX?
Volumio should see and automount the USB drive, no need to edit and save files.
Yeah… it is working as it should be. HDD and internetradio. Fantastic sound quality. Now I’ll start building and organizing the music collection.
Don’t know what happened but the new HDD formatted in FAT was fetched at once, as you said, and what made the Meridian Explorer2 starting to give beautiful sound 
but I’am a happy man now. My wife is happy too, all CD can be stored on the attick once put on the HDD. Thanks, next step might be NAS.
Paul
If you’re using the nano text editor to make the changes in things like fstab, yes ctrl-x is the way to exit it, and save the file along the way when you do so (it will ask you whether you want to or not, if you have unsaved changes made).