Changes to the Apple Macintosh OS X operating system, starting with 10.8.3 (Mountain Lion) have impacted how Java Web Start applications, such as the Download Manager used by TCIA, are run. If you encounter problems running Download Manager from within Mac OS X, these instructions may help.
Apple no longer distribute Java with Mac OS X. If your system does not have Java installed, please install the Java Runtime Environment (JRE) before attempting to use TCIA's Download Manager. A common JRE, including the one TCIA is tested with, can be downloaded for free from http://www.java.com.
Step-by-step guide