If you encounter a "Java Launch Error" or "File Not Found" specifically for version 1.20.1, try these steps:
mods (like Replay Mod or specific performance tools) on Lunar 1.20.1: Launch Lunar Client and select the Open Mod Settings: lunar client jar 1201
Earlier builds sometimes struggled with conflicts between popular Lunar mods (like ArmorStatusHUD or Keystrokes) and the base game code. Build iterations around the 1201 mark squashed several bugs related to: If you encounter a "Java Launch Error" or