The variable *debug-initialization-errors-in-snap-shot*
controls whether, in an image which is configured to start the LispWorks IDE automatically, an error during initialization is handled and displayed in a snapshot debugger after the IDE starts.
If the value of *debug-initialization-errors-in-snap-shot*
is nil
LispWorks behaves like LispWorks 5.0 and previous versions. That is, it attempts to enter the command line debugger.
LispWorks User Guide and Reference Manual - 20 Sep 2017