Computer name keeps changing OSX 10.10 (14A389)
Go to Macintosh HD > Library > Preferences > SystemConfiguration
and delete the following files:


com.apple.airport.preferences.plist
NetworkInterfaces.plist
preferences.plist


Then reboot the Mac.

The host names should be recreated correctly.

(According to http://forums.imore.com/os-x-yosemite-10-10/304804-my-computer-name-changing-10-10-a.html these are instructions provided by an Apple tech.)