Unfortunately at this time MAC OSX 10.10 is not an officially supported platform which may cause many issues. No official testing has been done to date with our latest version of IDL (8.4), therefor 8.1 may be very unstable and difficult to troubleshoot. Older MAC OSX license files utilizes an on-demand system service coupled with our FlexNet licensing manager in an attempt to causes the Exelis license manager service to attempt to relaunch if the service dies unexpectedly. It seems like the service is attempting to restart as needed but not connecting properly, this may be due in part to a configuration issue not locating the correct launch daemons. Newer MAC Node locked license files not not function in this manner and no longer require the use of these particular services. Below are two links that may further assist in the compatibility and configuration issues. Is ENVI 5.2 / IDL 8.4 compatible with Mac OS X 10.10 Yosemite? http://www.exelisvis.com/...d/14200/Default.aspx How to manage and update the IDL 8.2 / ENVI 5.0 license manager service on Mac OS X http://www.exelisvis.com/...cleID/4646/4646.aspx