If you have access to another PC, you can go to MS and create a new USB key image. Appears the USB image is corrupted. Also, trysetting the BIOS to default. Does the disc show in BIOS, not in boot options but in the overview page?
If you copied files over they may have been marked read only. You need to give them read/wrirte. Not sure how to do it for a whole nested directory but I'm sure if you check on the internet the instructions can be found.
I think it's better but ran the beta for it so I was used to it. It does take a little while to get used to the differences.
Glad you sorted out your issue, may have happened on an update. Like anything time fixes a lot of things.
Try this click view and in the top then navigation on the left. There are some option there play with them to see what you like. They are on off check mark on, open pane off.
External USB case at Newegg
https://www.newegg.com/p/0VN-05HJ-00003?Description=dvd%20external%20case&cm_re=dvd_external%20case-_-9SIAMKXEDY5495-_-Product&quicklink=true