Following my post yesterday, I downloaded the previous build
https://kd6kxr.keybase.pub/RawTherapee_macOS_10.14_x86_64_5.8-3034-g8bd9bddfc.zip
and installed successfully with no crashes so far.
I am very happy about this.
My installation process today was slightly different as I followed the readme instruction exactly and copied rawtherapee-cli to the hidden /usr/local/bin location.
I had not done this in previous installation for the following reasons:
I don’t really know what I am doing
The readme text was an rtf and I didn’t know how to read them on mac
The path /usr/local/bin didn’t exist on my machine.
I changed the extension rtf to txt and could then read the instructions contained, I created the bin folder as a subfolder of local folder and pasted rawtherapee-cli there.
All seems to be functioning well. Thanks again to all who have made this possible.