I'm trying to install Teensyduino to jump over some code for a project I'm interested in, bit not having much luck getting it to run. I have Arduino IDE 1.8.12 installed on Mac OS X 10.15.4, and that IDE works fine.

Download Teensyduino 1.52
Unzip in the downloads folder
Copy to the Applications folder
Delete Arduino IDE
Run Teensyduino (click on the web download security prompt to Open)
Teensyduino starts to load, and goes through 'Initialising Packages,' 'Preparing Boards' and 'Starting' and then just quits.

Am I missing a step or some other config I need to do?