Post back the Full Report - copy and paste - using the Additional Text Icon ( 3rd Icon to last ) The Report will Not Reveal Any Personal Information. It will take a Snap Shot - both the hardware and software. Run the application with Full Disc Access ( Security & Privacy - Full Disc Access ). The application is free or paid from added features. Suggest downloading the Application Etrecheck directly from a well Respected ASC Contributor.

IMHO - a Time Machine Backup to roll back the the computer in time may or may not solve the underlining issue

If as one writes above the Terminal Command are getting Stuck - IMHO this computer is seriously compromised. Or better yet, are there some plist file or cache that can be removed to reset this particular program (the update manager)? Is there a way to use Time machine to reset the computer to a few weeks ago, before this error happened? When trying 'softwareupdate -fetch-full-installer -full-installer-version 11.6.2 ', the only output is: The terminal gets stuck in the same manner, outputting only: 'Finding available software'.

My apple software update not working