I've been having troubles with STEP files since upgrading to 2015. Our EE uses Altium to design the controls, and would send me STEP files to do interference/fit checks. With 2014, when I opened the STEP file, Solidworks would parse the file and break it down to all the components, which I would then save all parts and the assembly to load it into other assemblies to check. Now, when I try to open STEP files, Solidworks says the default template is not valid and asks if I would like to proceed with a blank template. If I do, I just get a blank file containing nothing. This happens even with old STEP files that worked perfectly fine before. Any ideas?
change you system setting to either point to a valid template for the default, or switch from "always use default.." to "prompt user..."