Fix "Missing Dependency" and Mod Conflict Errors

"Missing dependency" means a mod needs another mod to run, and that other mod isn't installed. The server won't start until you add it.

How to fix it

1. Open Console and read the startup error. It names the missing mod.
2. Open Mods Installer, search for that exact mod, and install it. Match your loader (Forge, Fabric, or NeoForge) and your server's Minecraft version.
3. Restart the server.
4. Check Console again. If it starts clean with no errors, you're done.

Common causes

• A "library" mod is missing. Some mods need a shared library mod installed alongside them (for example Moonlight Lib or corelib). No library, no start.
• You removed a mod others needed. Other mods can depend on one you deleted. Reinstall it, or remove the mods that needed it.
• Wrong loader version. A Forge build of a mod won't work on a Fabric or NeoForge server, and vice versa. Double check you grabbed the right one.
• A client-only mod ended up on the server. Some mods (like Sodium) only belong on the player's own game, never the server.
• The Minecraft version changed. A mod that worked before can stop working after you change your server's version.

Take a backup before adding, removing, or updating mods. If something breaks, you can roll straight back instead of troubleshooting under pressure.

Still stuck?

Console doesn't clearly name the missing mod: see How to Read the Crash Log for help finding it.

Building a modpack from scratch: use How to Install a Modpack instead, it installs dependencies for you.

A plugin won't load: that's a separate system from mods, see How to Install Plugins.

Still won't start after all of this: open a support ticket with your crash log attached. Our team can trace the exact mod that's failing.