Fixing the Terralith Intro Message Still Showing After Installing the Mod

Rule out the common causes first

The message is sent once, at world creation, so most "it doesn't work" reports come down to the mod not being active at the moment the world was made, or to a loader mismatch.

Checklist

• Loader mismatch: a Fabric build will not load on NeoForge/Forge and vice versa. Verify the file matches your launcher profile.
• Wrong instance: if you use multiple profiles or a modpack launcher, the file may be in a different instance's mods folder than the one you launched.
• Mod disabled: some launchers let you toggle mods off without deleting them. Check it is enabled.
• Dependency issues: if the mod fails to initialize because a required library is missing or the wrong version, it will not run and the message returns. Read the latest log for load errors mentioning the mod.
• Testing method: create a fresh world each time. Re-entering an existing world proves nothing, because the intro message only fires on generation.

If all of the above check out and a brand-new world still prints the message, temporarily remove other mods that also inject chat messages on world load to isolate a conflict, then re-add them one at a time.