Hey there. New to mapping. I just want to edit a CTF map to make a portion of it a no-build zone using func_nobuild. I've been told how to do that and where to get Hammer. I downloaded the source SDK launcher from Steam. When I open Hammer and try to open a map, at first it says that there will be missing detail or something, then it gives me a message like this: 'Fatal error: Model... briefcase.mdl is missing...' I can't possibly conceive how and what to do in this scenario. I've tried verifying the files already to not avail. The change I want to make is really minor in comparison to what you guys do, but at this point, it's a software error more than anything really. Would love some answers!