Hi everyone,
jtisdel has reported a crash when using ABCreator under macOS High Sierra:
http://forums.wolflair.com/showthread.php?t=59916
I don't have High Sierra myself, so it's hard for me to test this. If anyone else is running High Sierra, can you please try opening a definition file for any game system (for example, the 40k game system definition file) and let me know if it works, or if you crash? Please also let me know the full version number of High Sierra you're running (you can find this on the "About This Mac" page).
Thanks for your help!