Some users report adding -Dzomboid.debug=true to a custom .bat file that launches the game, but the JSON method is cleaner.
If you need debug mode for Build 42 – whether to test mods, spawn items, or recover a bugged save – here’s the method that still works. The old -debug launch option is gone in B42, but there’s a new way. how to enable debug mode project zomboid build 42
Remove that line from the JSON file.
Hope this helps other survivors test B42 without frustration. Some users report adding -Dzomboid