Reason Version 8.2 and later only supports 64-bit operating systems and cannot be run in 32-bit mode.
Reason Versions 6 to 8.1 supports both 32-bit and 64-bit operating systems. On Mac OS X, the Reason (Version 6 to 8.1) application itself includes both 32-bit and 64-bit resources. This means the program will run in 32-bit or 64-bit depending on your operating system – you don’t actually need to do anything when installing the software.
It might be desirable to run the 32-bit version even under a 64-bit OS (for example if you’re using Reason with ReWire and a host that only supports 32-bit ReWire). In this case, you can force the program to run in 32-bit mode in the following way:
When you now launch Reason it will run in 32 bit mode.