Hi Rich, I noticed that a colleague of mine has taken your support request. I'm adding here his answer for other readers to see: For IDL 8.2.x, the licensed Advanced Math and Stats(IMSL) module is not available on Mac OS X. The last 32-bit version of IDL for Mac OS X is availablewith IDL 8.1. Also, since the IMSLmodule is not yet available for 64-bit IDL on Mac, users needing access to theIMSL module on Mac would need use 32-bit IDL 8.1. FYI, there is a feature request (issue ID:"IDL-57278") asking for 64-bit IDL for Mac support for the Advanced Math and Stats module. We are hoping that this will be available for a future version of IDL. I hope this helps. Thanks, Fernando