Nearly every operation and function in EnSight is initially set to a default value. Preferences allow you to set these initial values as well as set some default behaviors such as which time step to initially load for transient data, how the mouse buttons are defined, etc. When EnSight starts, the preference settings are read from the $CEI/ensight242/site_preferences directory and then overlaid by the preference settings found in your EnSight defaults directory (located at %HOMEDRIVE%%HOMEPATH%\(username)\.ensight242 commonly located at C:\Users\username\.ensight242 on Win10, C:\Documents and Settings\yourusername\.ensight242 on older Windows, and ~/.ensight242 on Linux, and in ~/Library/Application Support/EnSight242 on the Mac).