How are you trying to load?
For example :
File - Open
File - Open As
Drag & Drop
Copy & Paste
I usually load with File - Open, but, I have tried with File - Open As, Drag and Drop and Copy and Past : it doesn't work...
If none of those are working I would try two thing in this order.
1. Reset Preferences (which you say in your first post that you have done)
2. Uninstall Photoshop - run the Adobe CC Cleaner tool and then re-install Photoshop.
Thank you : it works now !!!