Hi,
I've had a chance to look at this on the Mac, and have upgraded to latest Catalina.
The first time you try to run PSUD2, it will ask for access to the Documents folder. It needs this access to store the rectifiers and example files. If you say "No" at any stage, the access will be blocked and the error messages you show in your post will be displayed. MacOS won't ask you again, once you've said No, that's it, there is no second offer....
There's a way to retrospectively fix it by going into Security and Privacy settings which you can do by pressing Apple menu > System Preferences > Security and Privacy > Privacy tab. Scroll the left panel down until you get to a blue folder icon with the title "Files and Folders". Click it and the right hand panel will now show a list of apps and their access privileges. Scroll down to PSUD and make sure the box is ticked.
Hopefully there's a screen dump attached to show the screen I'm talking about. (It shows unchecked which
wont work and that may be how yours looks, check the box and it try a reinstall of the .DMG file, should get things going again)
The following Apple article contains a bit more information about application access ->?
Hope this helps, please let me know if it fixes the issue.
Regards,
Duncan
