Do you have a Mac computer that keeps changing its sharing name or tells you that another device on the network already has the name of your computer? This can occur if the Mac is connected to the network using more than one active interface. That is, if the Mac is connected to both ethernet and wi-fi. A Mac will attempt to share its name from both interfaces. When the Mac sees that the name is already on the network it will get stuck in a continual cycle of trying to rename itself. The solution is to only connect to the network via one interface at a time. That is, either turn off the wi-fi when plugged into ethernet or unplug the ethernet when using wi-fi.