MultilaunchWarning

MultilaunchWarning is a global option that determines if a warning is given when you try to modify user preferences while running two copies of Mathematica simultaneously.

The purpose of this warning is to make the user aware that there is only one user preferences file per user. If more than one copy of Mathematica is running, changes made to this file may be overwritten by the different copies alternately, resulting in lost user preferences. The warning is given only when Mathematica tries to write to the preferences file, for example, when you change the setting for a global option in the Option Inspector.

With the setting MultilaunchWarning True, a warning is given when Mathematica tries to write to the preferences file, if the same file is in use by another copy of Mathematica.

With the default setting MultilaunchWarning False, no warning is given when Mathematica tries to write to the preferences file, even if the file is being used by another copy of Mathematica.