⚠️ Do not use Steam tModLoader with GOG Terraria – they expect different registry keys.

Solution: Download tModLoader directly from GitHub or the official forums. Install it into a separate directory (e.g., Terraria Modded). Point the tModLoader executable to your GOG Terraria data folder. The GOG version is more mod-friendly than Steam once configured.

tModLoader (the official mod loader) supports the GOG version natively. However, many mods stabilized around 1.4.4.9 because later minor patches sometimes broke API hooks. The GOG version allows you to lock your game to the most compatible patch level for massive mods like Calamity or Thorium.