Open the World page and tick No map in the Difficulty card. Choose Save and restart the server. The wiki says players then cannot use the map or the minimap in the game. The change applies at the next start. More about the game: Valheim servers.
Turn it on
- Open the World page.
- In the Difficulty card, tick No map (1).
- Choose Save (2). The panel says: “Saved. The game reads these when it starts, so restart the server to use them.”
- Choose Restart at the top of the server page.
- Tick No map
- Save
The setting belongs to the world, so players change nothing on their side. The wiki notes that it makes the game harder than intended.
The panel Map page
The Map page in the panel is separate from the game’s map. The panel draws it from the world’s seed and its last save, and the seed and save line is at the top.
- Seed and save
Turn it off
A world remembers the modifiers it was started with. Unticking the switch later does not remove it. The card shows what the world holds: “The world remembers: …”.
- Untick No map.
- Tick Clear the world’s own modifiers first.
- Choose Save and restart.
The world then gets exactly the settings on the page. Any other switch or modifier you want must be set on the page as well.
By hand
The panel writes -setkey nomap on the start line. It is one of four switches in the game’s own manual. The others are nobuildcost, playerevents and passivemobs.
If it does not work
- Players still see the map. Restart the server. A saved change is read at the next start.
- No Save button. Your role may not allow editing the startup settings.
- The map will not come back. Untick No map, tick Clear the world’s own modifiers first, save and restart.
- The panel Map page is empty. The world may not be saved yet. It says “The world has not been saved yet.” See the server map.
More settings: world modifiers.
Sources: valheim.fandom.com: World Modifiers