Community
There appears to be a problem with the shared parameters used in certain manufacturer's family. If you try to load multiple families into a project with different shared parameter GUID the program crashes. This has occured for me while using the McQuay chiller family and a pump family (Patterson) that I've downloaded from the seek.autodesk site. I've been directed to this post http://forums.autodesk.com/t5/Autodesk-Revit-MEP/Mismatched-shared-parameter-definitions/td-p/347274... after I subbmited a support request if anyone else is having this issue.