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/ensight252/site_preferences directory and then overlaid by the preference settings found in your EnSight defaults directory (located at %HOMEDRIVE%%HOMEPATH%\(username)\.ensight252 commonly located at C:\Users\username\.ensight252 on Win10, C:\Documents and Settings\yourusername\.ensight252 on older Windows, and ~/.ensight252 on Linux, and in ~/Library/Application Support/EnSight252 on the Mac).