I thought I would give Retrospect another try, I used it years ago on an early PPC machine using a tape drive. It was wonderful for years. Saved my data several times. Then sometime after version 6 thing got very unreliable and I moved on.
I like a lot of what the current version should be able to do for me and thought I would give it another try.
On my Mac Pro (2013) running macOS 10.14.6, the 18.104.22.168 installer, installs a single file /Library/Application Support/Retropect/configs.xml and quits. No app. No login items. No launchd .plists. No console messages. Nothing.
I don't have time to debug what should be a VERY reliable app, it is for backups after all. At least failing quick saves me time and I appreciate that at least.
I'm sorry to be moving on for good.