How to install MT4 on Mac/macOS Catalina: https://www.youtube.com/watch?v=48THde8Olg4
1) Open Terminal (search at top right in Spotlight to launch Terminal)
2) Type the command: xattr -d com.apple.quarantine and add a space
3) Drag the file into Terminal after the space.
4) Press enter.
5) Double click the app to launch it.
1. Executing the terminal command "xattr -d com.apple.quarantine /Applications/Global\ Prime\ MT4.app" removes it from quarantine imposed by OS on this type of application (this is explained in the video).
2. If there is still a problem, follow these instructions to disable SIP: https://www.imore.com/how-turn-system-integrity-protection-macos - Catalina is a 64-bit application only and MT4 is still 32 bit. SIP is preventing the application to virtualize the 32 but environment. So it needs to be shut down. This should only be required with newer Mac models.