tModLoader still runs Terraria 1.4.4.9, so it cannot open a world that Terraria 1.4.5 saved. A world you played on Terraria Vanilla or TShock recently is in the 1.4.5 format. Start a new world on tModLoader, or keep that world on Terraria Vanilla or TShock. The panel checks this when you switch to tModLoader and stops the switch before anything changes.
When you switch to tModLoader
If you keep your files when you change to tModLoader, the panel reads the world named in World Name first. If Terraria 1.4.5 saved it, the window says Nothing was changed: your world is at risk and explains:
tModLoader still runs on Terraria 1.4.4, and your world with the world's name was saved by a newer Terraria, which tModLoader cannot open.
Your choices:
- Start clean instead: begin a new tModLoader world. A safety backup of the world is saved first when your plan has room for one.
- Keep my files and install anyway: then change World Name in Game Settings before you start, so tModLoader creates a new world beside the old one, which stays on disk.
- Choose another version, or close the window and stay on Terraria Vanilla or TShock, which open the world.
Already on tModLoader
If the server loads a 1.4.5 world anyway, it does not start properly. Change World Name to a new name, or to a world made by tModLoader, and restart. See How to start a new world on your Terraria server.
Keep both
To play the 1.4.5 world on Terraria Vanilla and a modded world on tModLoader, keep two setups and switch between them: How to use instances to switch between worlds.
Good to know
- This lasts until tModLoader moves to Terraria 1.4.5. Until then, a world cannot go from 1.4.5 back to tModLoader.
- A world made on tModLoader opens on Terraria Vanilla, but without its modded items and blocks, which are in the
.twldfile. - Download your world before you change type, as the panel advises: How to download your Terraria world.
