Outdated mods, corrupt save files from spawning unused item can lead to CTD.

Would suggest, always back up your save files before start modding.

at one point there, the webroot antivirus had labeling mhw.exe as a malware due to capcom's bonehead drm idea, so if you just recently started using a new AV, check that it's not blocking MHW.EXE, they're probably not the only vendor that flagged it.