Why does Yosemite add a number to my system name and how do I stop it? I named my system "Foob" on my 2012 MacBook Pro. Yosemite has renamed it "Foob (4)".  I wasn't sure where that "(4)" came from so I renamed it back to "Foob" in the Sharing Preferences. But, I looked today and it's now at "Foob (2)"

Why is it doing this? How can I stop it?
Check the answers here. (I don't have the reputation to mark this as a duplicate.)