Use CrossOver or Wine to emulate a Windows environment and execute the installer. Method 3: The Legacy Account Archive
If your Mac is running macOS Mojave (10.14) or older , you are safe. If you have Catalina (10.15) or Big Sur (11.x), you cannot run FL Studio 12 natively. You would need FL Studio 20.8 or newer. Download Fl Studio 12 Mac Os X
Image-Line released a "Native macOS 64-Bit Alpha" for version 12.5.1. It was intended for testing and lacked many essential stock plugins (like Fruity Compressor). Crossover Wrapper: Use CrossOver or Wine to emulate a Windows