How to Fix Invalid World Type
An unknown level-type in server.properties doesn't stop the server. It logs a warning and generates a normal world instead. Here is how to set a valid preset.
Quick Fix
Stop the server, set level-type to minecraft:normal, minecraft:flat, minecraft:large_biomes, minecraft:amplified or minecraft:single_biome_surface, and give it a new level-name so it generates a fresh world with that preset.
Error Message
Failed to parse level-type amplifed, defaulting to minecraft:normalHow to Fix
Open server.properties and set level-type to one of the vanilla presets: minecraft:normal, minecraft:flat, minecraft:large_biomes, minecraft:amplified or minecraft:single_biome_surface. The minecraft: part can be left out.
Don't worry if the saved file shows minecraft\:normal with a backslash. The server writes the file in Java's properties format, which puts a backslash before a colon, and it reads both forms the same way.
Give the server a new world to generate: change level-name to a new folder name, or move the old world folder out of the server directory. The preset is only applied when a world is created.
For a superflat or single biome world, put the layer or biome settings in generator-settings; for the other presets leave it at {}.
If the preset comes from a mod or data pack, make sure it is installed and enabled before the world is generated, then check the log again for the warning.
Common Causes
- A typo or unknown name in level-type. The server doesn't stop: it writes "Failed to parse level-type ..., defaulting to minecraft:normal" to the log and generates a normal world.
- A preset that came from a mod or data pack that is no longer loaded, so the name doesn't exist when the world is created.
- An old name from a config made for a much older version. Of those, the server only translates default and largebiomes; flat and amplified work because the minecraft: part can be left out.
- The world already exists. level-type is only used when the server generates a new world, so changing it later seems to do nothing.
Diagnostic Steps
- Search the server log for "Failed to parse level-type".
- Compare the value in the warning with the list of valid presets.
- Fix level-type in server.properties.
- Point level-name at a new folder, or move the old world away.
- Start the server and check that the warning is gone.
FAQ
What world types are available?
On a vanilla server: minecraft:normal, minecraft:flat, minecraft:large_biomes, minecraft:amplified and minecraft:single_biome_surface. Mods and data packs can add more.
Why didn't changing level-type change my world?
level-type is only read when the server generates a new world. An existing world keeps the generator it was created with, so the setting needs a new world folder to take effect.
Does an invalid level-type crash the server?
No. A vanilla server logs a warning and generates a normal world, which is why the mistake is easy to miss until you notice the world isn't flat or amplified.
