In zoom 5.0 this trick from above works perfect. I don’t know if it works for ManyCam, but I have a Black Magic UltraStudio Mini Recorder and it does allow it to work.
- Update Zoom to the latest version
- Install Xcode via Terminal “Xcode-select --install”
- Once installed make sure Zoom is closed and run this in Terminal “codesign --remove-signature /Applications/zoom.us.app/”
- Launch Zoom and try virtual cam or Blackmagic capture device