System Extension Cannot Be Used

[trevor]

Connect those external volumes to your Mac and boot it. Then, copy/paste the following commands into your Terminal in one big block:

ls -alOe /Volumes
diskutil list
id
echo "done"

Let us see the results.

Oh, and when you say 'Then need to be accessible from any computer', do you mean by any account including non-admins on any computer? In other words, the most permissive permissions possible?

Trevor