Minetest server will not start or players see unknown blocks

Minetest tells you what went wrong in the console. Read it first, then work through this list.

1. The server will not start after a mod change

1. Open the Console tab and read the first lines after a start attempt.
2. A missing dependency is named directly. Install that mod as well.
3. A Lua error names the mod and the file.
4. Remove the load_mod line for that mod in world.mt, start the server, then look for a version of the mod that suits your Minetest version.

2. A mod is installed but does nothing

• Every mod needs a load_mod_<modname> = true line in world.mt.
• The name must match the folder name exactly.
• Restart after editing, since the file is read at world load.

3. Players see unknown blocks or items

This means the world contains content from a mod that is no longer enabled. Put the mod back and restart, and the blocks come back as they were. Building over unknown nodes destroys them permanently, so fix it before playing on.

4. Players cannot build

They are missing the interact privilege. Either grant it with /grant PlayerName interact, or add it to default_privs in minetest.conf so new players get it automatically.

5. The server is not in the public list

• server_announce must be true in minetest.conf.
• server_name and server_description should be set, or the entry is hard to find.
• Give it a few minutes after a start, and use the address and port in the meantime.

6. A player forgot their password

Accounts belong to the world, so only the server admin can help. Clear their password from the admin account and let them set a new one on their next login.

Open a ticket from Support in the Client Area with the last 50 lines of console output if none of this fits.