Unless explicitly shut down, a server will continue to run in the background on most systems. On Windows, closing the server console window will kill the server, but on other platforms the server may continue to run. Ensure that you manually shut down servers that you no longer need. When you are done using the server, you can stop it in the Template Editor by selecting Tools > Stop local Nexus server from the menu bar. Note that this will shut down only the server you are currently connected to.