Cubase 12 Pro 12.0.52 freezes at Scanning VST3 plugins

In Monterey OS Cubase Pro 12 freezes when initializing: Scanning VST3 Plugins, and won’t open. Using a Mac Pro.

Thought it had frozen first time I tried. Turned out it just took a long time (like 10 mins, depending how many plugins) with no progress indicator, but it got there in the end.