Mac mini (Mid 2011) and Mac mini Server (Mid 2011): Does not go to sleep when Thunderbolt to Ethernet Gigabit Adapter is connected

When a Thunderbolt to Ethernet Gigabit Adapter is connected to a Mac mini (Mid 2011) or Mac mini Server (Mid 2011), the Mac mini will not go to sleep. It cycles rapidly between sleep and wake.

Do not put the Mac mini to sleep while the Thunderbolt to Ethernet Gigabit Adapter is connected. Disconnect the adapter before putting the computer to sleep.

When using a Thunderbolt to Ethernet Gigabit Adapter with a Mac mini (Mid 2011) or Mac mini Server (Mid 2011), set Computer Sleep to "Never" in the Energy Saver System Preferences pane. This is the default setting on a Mac mini Server.