I regard to corrupt files. If I try to do an Import of a Corrupt Rhino file, I get the dialog
FILENAME has anunreadable geomery objedt. Do you want to continue reading geomtry objects?
If I click YES, the dialog box acts like a system modal dialog box that blocks every application on the system.
Hopefully you setup a backup system like Time Machine for your Mac so you have a good copy the file.
Generally, struggling with damaged files like you described is a waste of your time and effort.
Yes, I am using Time Machine a lot these days. It would be helpful not to have the dialog box not take over the computer while I try to see the file is recoverable.