Ah, but dayglored macOS High Sierra DOES NOT automatically reformat any USB drives or external SSDs to APFS that are just inserted in, or connected to a High Sierra Mac. That's not what it does.
The limitation is that macOS Sierra and older OS Macs cannot directly read from or write to the upgraded macOS High Sierra APFS formatted drives. . . but the macOS High Sierra computer is not limited from writing to and reading from standard Mac HFS+ drives either internal or external, or on other Macs.
This is actually the second time Apple has had to do this. The first time was when Apple moved from the old Apple file system of MacOS to HFS+ back in January 1998. The complaints were similar then because the old HFS could not be used for booting. . . but it had to be done in one fell swoop.
> ... macOS High Sierra DOES NOT automatically reformat any USB drives or external SSDs to APFS that are just inserted in, or connected to a High Sierra Mac... The only drive that will be automatically reformatted to APFS is the boot drive of the Mac where Apple macOS High Sierra is being installed.
Okay, that's fine.
> Any subsequent USB drives or SSDs that will formatted using the DEFAULT APFS formatting command. The ability to format in HFS+ is still available in High Sierra.
So for all other drives (other than the boot drive), I would have to explicitly format in HFS+, because the default would be to format in APFS. That's okay too -- one should always "measure twice, cut once" when formatting. :-)
Swordmaker, I sent you a private mail about a Mac issue Im having. If you have time, would you give me your thoughts please? Thanks in advance.