The operating system boots from the drive without any problem.
The formatting is GUID & Extended Journaled.
I tried making a disk image and received the same error.
I ended up searching my main system drive for all related files for each program installed and manually duplicating the folder structure then copy/pasting the files in the external drive. I was successful in getting everything to run off the new drive.
It is frustrating that an answer to this problem does not pop up online after a search. It has to be a common problem when people attempt to create a bootable external drive loaded with software.
FWIW, I did not want to do any sort of cloning. I wanted a fresh installation. Fortunately the software from the bundle that is currently installed on my original main drive is healthy as far as I know. If I needed a fresh installation of it I would not have been able to use this approach.