sometimes people go on mod sprees, they download all sorts of cool stuff to their own pre existing mod pack and then bam, the game doesnt load, for anyone technical its as simple as checking the crash log but even then this doesnt always work, so perhaps have a system that checks when an instance successfully loads and stores it in memory if your game crashes you can revert to the previous instance, and you will be given a list of all the mods you downloaded since the functional instance was loaded making "debugging" substantially easier