MAC OS X 10.7 (Lion) and subsequent versions of the operating system no longer support Power PC Applications. Because the demo for ReadIRIS is for an older version (ReadIRIS 11), it is not compatible with the newer MAC OS X 10.7 and above.The full version of ReadIRIS that you get when you purchase the software is for a newer version, however, which is no longer a PowerPC Application and compatible with OS X Lion.