How to Change the Seed on a Valheim Server (Keep Your Old World)

You cannot change the seed of an existing Valheim world, because the terrain is generated from the seed stored in the world's metadata (_main.N.fwl2 in 1.0 worlds, <World>.fwl before). To use a seed you choose, create a new world with it in Valheim on your PC, load it once, then upload its folder from worlds_local into the server's worlds_local and set the server's world name (-world) to that exact folder name. The dedicated server has no seed option, and your old world stays on disk.

What you can change on an existing world

Characters are not part of the world. They are saved on each player's own device in characters_local, so everyone keeps their skills and gear when you move to a new seed.

Why can't the server just use a new seed?

Valheim's dedicated server takes -world, -name, -password, -preset, -modifier and a few other launch options, but not a seed. When -world names a world that does not exist, the server creates one with a random seed. Changing the seed on the existing world is impossible either way: everything you built, dug and explored is stored as changes on top of terrain generated from that seed, so a different seed would put your base inside a mountain or out at sea.

So the only route to a chosen seed is: make the world in the game client, then hand it to the server.

What goes where

Linux and Steam Deck players find the same folders in ~/.config/unity3d/IronGate/Valheim/. More paths, including cloud saves, are in Valheim world save location.

Step 1: Back up the current world

Stop the server and download your current world folder from worlds_local. It will stay on the server anyway, but a copy on your PC is the real safety net. On GamezServers, press Backup too.

Step 2: Create the world with your seed

1. Launch Valheim on PC, click Start Game and pick any character.
2. Click New World, type a world name, and replace the random value in the Seed field with your seed. Seeds are short strings, for example HHcLC5acQt.
3. Make sure the world is saved locally, not to Steam Cloud, so the folder appears in worlds_local.
4. Create the world, load into it and wait a minute or two, then quit to the main menu. That forces a complete save. A world you create but never load may not have all its files yet.

Step 3: Upload the folder to the server

1. Open worlds_local on your PC and find the folder with your new world's name.
2. Upload the whole folder into the server's .config/unity3d/IronGate/Valheim/worlds_local/. Never upload single files out of it, the folder is one unit.
3. For a pre 1.0 world, upload the .fwl and .db pair together.

Step 4: Point the server at the new world

Set the world name to the folder name exactly, same spelling and capitals. On a self hosted server that is -world "MyNewSeedWorld" on the start line. On GamezServers it is World name in Settings. Start the server, join, and check that the spawn area looks like the seed you picked.

Your old world is still in worlds_local. Set the world name back to its name whenever you want to return.

The gotcha: world modifiers come from the server, not your new world

When you create a world in the client, the screen also offers World Modifiers such as Hard combat or More resources. People set them carefully, upload the world, and find the server playing it on Normal. A dedicated server takes its difficulty from its own launch line, -preset first and then each -modifier, and a server that starts with -preset normal (our default) plays the world on Normal whatever you picked in the client. Iron Gate's server notes say a preset overwrites earlier modifiers, so order matters.

Set the difficulty on the server itself after uploading. On GamezServers that is Difficulty preset, plus Combat, Death penalty, Resources, Raids, Portals and No map in Settings. Details are in Valheim world modifiers on a dedicated server.

How do I find the seed of my current server world?

Download the world folder and put it in worlds_local on your PC. Valheim's world list shows each world's seed next to its name when you select it, without loading the world. That is also how you can share your seed with friends who want to plan routes on a seed map viewer.

Common problems

• Server made another random world: the world name does not match the uploaded folder name exactly, or the folder landed one level too deep, like worlds_local/upload/MyWorld.
• Same terrain as before: the server is still loading the old world. Check the world name setting and restart.
• Modifiers missing: the server's launch options decide them. Set the preset and modifiers in the panel.
• World missing on your PC: it was saved to Steam Cloud. Use Manage saves in the world list to move it to local storage.
• Wrong version error on load: the world was created on a different game version from the server. Update Valheim on both sides first.

On GamezServers

On a Valheim server from GamezServers, upload the world folder from the Files tab or over the SFTP login in Settings, set World name to match, and press Restart. Click Backup before switching, and both worlds stay on the server so you can swap back. For the full upload walkthrough, see how to upload a Valheim world to a dedicated server.

FAQ

Can I change the seed of an existing Valheim world?

No. The seed is fixed when the world is created and the terrain depends on it. Create a new world with the seed you want and upload it.

Does a Valheim dedicated server have a seed setting?

No. There is no seed launch option. The server picks a random seed when it creates a world, so make the world on your PC to choose the seed.

Will players keep their characters on the new seed?

Yes. Characters are saved on each player's own device, not in the world, so skills and inventory come with them.

Can I reset my Valheim world but keep the same seed?

Yes. Create a new world with the same seed and a new name on your PC, upload it, and point the server at the new name. The terrain is identical but untouched.