SQLCMD - Access is Denied After Running Script

I'm working with a vendor about this, but a supplied script that they have to run to upgrade their software, after running, ruins access to SQLCMD. Before running the script I can open a Command Prompt window > SQLCMD > Drops me in. After running their scripts, when attempting to do the same thing, get the error: Access is Denied I've tried dropping a copy of SQLCMD.exe from a known good working server into same location where the affected server was, but even trying to manually invoke it from the location, receive a: "Windows cannot access the specified device, path, or file. You may not have the appropriate permissions to access the item". Going to permissions > Security, it has all the same permissions as the known good working file, as is the entire directory path. So obviously osmething deeper, but I cannot / do not know where to start to diagnose.