We just upgraded to SW2015 (I know I am almost a full release behind, but we are all puppets of our corporate overlords).  Everybody here has the same complaint.  Pack and go is no longer available in windows explorer.  The only way to use pack and go is to open the file and use pack and go from within solidworks.  This is a pain, especially with larger files that take a while to load.  After a search on these forums I found some older references to the same issue from a few versions back.  The main solution listed was to make sure the file associations were to Solidworks Launcher.  That did not cure my problem.  Any other ideas?