config.json so you can open the game again https://github.com/tModLoader/tModLoader/wiki/Basic-tModLoader-Usage-FAQ#disable-all-resource-packsItem_1.png and Item_1.xnb or Music_1.wav and Music_1.mp3. Vanilla just ignores one of the duplicates, but tModLoader detects both and raises an error. To fix it, either remove one of the duplicate files or place one of the duplicate files in a non-standard folder so it won't be read by the resource pack system. If you are not the author of the resource pack, report it to the author so they can update the resource pack.