I have a border collie mix, and he has the same problems. He was never undersocialized with humans, we have many hospice nurses in my house every day, and friends and family that come over. Plus I used to bring him everywhere and people would just adore him. Now, anyone he didnt see almost every day for the first year of his life he acts viscious towards. When we have company over he either has to be outside or in his crate. Which I feel terrible about, but when it comes to family he is just the biggest baby ever, same with children. But adults he isnt very happy with. Some of my friends, every time they come over I have them feed him hotdogs or some other treats he loves when they walk by him in his cage hoping that this will make he know they arent bad. For those certain people, he doesnt growl at them as much anymore, and is really toned down on the barking. I hope eventually I will beable to have him roam the house free when I have friends over. :-/