The Envi preference file (envi.cfg) saves the default settings for Envi such as default data directory, default window size, default number of bins for histograms.
By default (on windows) this file is stored in the installation directory e.g. C:\Program Files\Harris\ENVI54\classic\menu\
On servers where several users use the same version of Envi, users often do not have the permissions to edit that file,
and consequently there is no way to change these type of settings permanently. I have been looking for a way of changing the location the envi.cfg file permanently so that my preferences are loaded on startup. I should mention that I usually only use Envi classic.