I had the same initial problem, and tried the solution suggested by avaddon. Like some other people here, it didn't work for me until I also followed the suggestion by emoryvincent, who suggested that... After avaddon's steps, I had to go to System Preferences / Security & Privacy / Privacy / Full Disk Access and then (once I'd unlocked the page by clicking on the unlock icon) I ticked next to RzUpdater. I think this allows the RzUpdater access to some administrative settings. I have no real idea what I was doing but it worked (eventually)!