How to Reset a Core Keeper Server World (Start a New World)

To reset a Core Keeper dedicated server, stop it and either point it at an unused world slot (change the world index, for example from 0 to 1) or delete or rename the current world file, such as 0.world.gzip, in the server's DedicatedServer/worlds/ folder. When the server starts and finds no world in that slot, it generates a new one using the world seed (0 means random) and the world mode (normal or hard). Players keep their characters, because characters are saved on their own PCs.

A fresh underground cavern in Core Keeper

Why groups reset

The usual reasons:

A new major update. Fresh biomes and bosses are more fun found in a new world than in one you already dug out.
Switching to hard mode. World mode is fixed when a world is created. You cannot turn an existing world into a hard mode world, so trying hard mode means a new world.
A world that got messy. Thousands of tiles of tunnels, half finished bases from people who left, or an experiment with mods that went wrong.
A new group. Different friends, fresh start.

Before you wipe, agree with the group. Somebody always had a farm they cared about.

What a reset keeps and what it loses

Thing	After a reset
The world: map, bases, chests, farms, bosses killed	New world, starts from scratch
Characters: level, skills, inventory	Kept. They live on each player's PC
The old world file	Kept if you switch slots or rename it, gone if you delete it
Server settings and Game ID	Unchanged

Because characters carry over, players arrive in the new world with the gear they had. If you want a true fresh start, ask everyone to make a new character too.

Where the world files are

The dedicated server stores each world as one file named after its slot number:

DedicatedServer/worlds/0.world.gzip
DedicatedServer/worlds/1.world.gzip

On Linux that folder sits under ~/.config/unity3d/Pugstorm/Core Keeper/DedicatedServer/. On Windows it is under %USERPROFILE%\AppData\LocalLow\Pugstorm\Core Keeper\DedicatedServer\. The world index setting (-world on the launch line, or world in ServerConfig.json) picks which slot the server loads.

Method 1: Switch to a new slot (recommended)

This keeps the old world untouched, so you can go back to it.

Stop the server.
Change the world index to a number that has no file yet. If the server ran world 0, set it to 1.
Set the seed and mode you want for the new world (next section).
Start the server. It finds no 1.world.gzip, so it generates a new world in slot 1.

To go back, set the index to 0 again and restart. Nothing is lost.

Method 2: Delete or rename the world file

If you want to stay on the same slot:

Stop the server. Do not skip this, because a running server saves its world again when it shuts down and can recreate the file.
Download a copy of 0.world.gzip for safekeeping.
Rename it, for example to 0.world.gzip.old, or delete it.
Start the server. Slot 0 is empty, so it generates a new world.

Choosing seed and mode for the new world

These only apply when a world is created, so set them before the first start of the new world.

Setting	Launch option	What it does
World seed	`-worldseed`	`0` picks a random seed. Any other number gives a repeatable map
World mode	`-worldmode`	`0` normal, `1` hard
World name	`-worldname`	The name shown for the world

Hard mode makes enemies much tougher. Decide as a group, since you cannot switch an existing world back to normal later. A known seed is handy if you want the same layout as another group, or as a world you played single player.

Keeping the Game ID the same

If the server uses a fixed Game ID, it stays the same through a reset, so friends join the new world with the ID they already have. If the server makes a new Game ID at each start, share the new one from the console or GameID.txt after the reset. Our guide to joining a Core Keeper dedicated server explains Game IDs.

Mods and resets

If the server runs mods, the new world is created with whatever mods are installed at the time. A reset is a good moment to change your mod list, since nothing in the new world depends on the old mods yet. Every player still needs the same mods as the server. See installing mods on a Core Keeper server.

Bringing an old world back later

Any world file can be loaded again by placing it in the worlds folder and setting the world index to its number. You can also take a world from single player and load it on the server the same way; moving a Core Keeper world to a dedicated server walks through it.

Resetting on a hosted server

On a GamezServers Core Keeper server, the reset is three panel settings: change World Index to an empty slot, set World Seed (0 for random) and World Mode (normal or hard), then restart. The old world stays in the worlds folder in the file manager, and a one click backup before you start means you can roll back even if you delete it. A fixed Game ID in the panel keeps your friends' join ID the same through the reset. Up to eight players run on 4 GB, and a bigger group can move up a plan without losing the world.

FAQ

How do I reset my Core Keeper dedicated server?

Stop it, then either set the world index to an unused slot or remove the current .world.gzip file. The server generates a new world on the next start.

Do players lose their characters when the world resets?

No. Characters are stored on each player's PC and keep their level and inventory.

Can I turn an existing Core Keeper world into hard mode?

No. World mode is set when a world is created. Make a new world with hard mode instead.

How do I get the same world layout again?

Use the same non zero world seed when the new world is created.