Reproducer for a crash:
Clone the GitHub libraries using the script in the kicad sources.
Set up the paths to point at the symbols, footprints and 3D packages
New project, new schematic
Add an ATMEGA32U2 to the schematic sheet.
1: click 'Cancel' through the following error dialog
Errors were encountered loading footprints:
footprint library path “/Users/jeff/work/KiCAD/library-repos/Connectors_Terminal_Blocks.pretty” does not exist
footprint library path “/Users/jeff/work/KiCAD/library-repos/Discret.pretty” does not exist
footprint library path “/Users/jeff/work/KiCAD/library-repos/Divers.pretty” does not exist
footprint library path “/Users/jeff/work/KiCAD/library-repos/IR-DirectFETs.pretty” does not exist
footprint library path “/Users/jeff/work/KiCAD/library-repos/Labels.pretty” does not exist
footprint library path “/Users/jeff/work/KiCAD/library-repos/Mechanical_Sockets.pretty” does not exist
2: click Yes on the following dialog box
Some of the assigned footprints are legacy entries (are missing lib nicknames). Would you like CvPcb to attempt to convert them...
Unhandled exception of unknown type
Clicking OK exits the program.