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Fix "Mod X requires Y" and missing mod dependencies

2 min readUpdated Nov 3, 2026Copy link

A mod needs another mod (or a specific version of one) that isn't in your mods folder. The error names both, so the fix is to add or swap one file.

Fabric stops with "Incompatible mods found!" and a line like:

Mod 'Example Mod' (examplemod) 1.4.0 requires any version of fabric-api, which is missing!

Forge and NeoForge log:

Missing or unsupported mandatory dependencies:
	Mod ID: 'geckolib', Requested by: 'examplemod', Expected range: '[4.4,)', Actual version: '[MISSING]'

and show "Mod examplemod requires geckolib 4.4 or above" on the loading error screen.

Why it happens #

• A library mod is missing. Many mods need a shared library: Fabric API, Architectury, Cloth Config, GeckoLib, Forge Config API Port and so on. Mod pages list them, but uploads often skip them.
• Wrong version. The library is there but too old or too new. Fabric says "but only the wrong version is present"; Forge/NeoForge shows the expected range next to the actual version.
• Wrong loader or Minecraft version. A Forge mod in a NeoForge server, or a 1.20.1 mod in a 1.21 server, can't satisfy anything.
• Client-only mods on the server. Minimaps, shader loaders and HUD mods are for players' games. On Forge this often crashes with Attempted to load class net/minecraft/client/... for invalid dist DEDICATED_SERVER; on Fabric the error says the dependency "is disabled for this environment (client/server only)".

Read the error #

Each line gives you three facts: which mod is complaining, which mod it needs, and which versions it accepts. In Forge's format, [4.4,) means "4.4 or newer" and [MISSING] means not installed. In Fabric's, "any version" means any build of that mod for your Minecraft version. Fabric also prints "A potential solution has been determined" with the exact file to add, remove or replace. Read that part first.

How to fix it #

1. Stop the server.
2. Download the missing mod from its official page on Modrinth or CurseForge. Filter by your exact Minecraft version and your loader (Fabric, Forge, NeoForge or Quilt).
3. Upload it into the mods folder with Files or SFTP (see uploading files). If the error was a version range, delete the old jar first so there aren't two copies.
4. Remove client-only mods from the server's mods folder. Players keep them on their own game.
5. Start the server and read the console. Fixing one dependency sometimes reveals the next one; repeat until it starts.
6. Running a modpack? Use the pack's official server pack instead of copying your client's mods folder. It has the right mods and versions already.

On ESN #

Your server type decides which mods can load: Fabric mods need a Fabric server, Forge mods a Forge server, NeoForge mods a NeoForge server. See server software to check or change it, and add plugins and mods for the upload steps. Modded servers also need enough memory: Forge needs at least a 2 GB plan on ESN, and big packs much more (see RAM guide).

FAQ #

What is Fabric API and do I need it?

It is a library mod most Fabric mods depend on. If an error says it requires fabric-api, download Fabric API for your Minecraft version and put it in the mods folder.

Can I copy my mods folder from my game to the server?

Not as is. Client-only mods like minimaps and shaders crash or are rejected on a server. Use the modpack's server pack, or remove client-only mods.

Why does it say invalid dist DEDICATED_SERVER?

A mod tried to load client-only code on the server. That mod is client-only, or needs a server-safe version. Remove it from the server.

Sources: Fabric Loader source: dependency error messages (checked Nov 3, 2026) · NeoForge FancyModLoader: missing dependency messages (checked Nov 3, 2026) · Fabric Wiki: troubleshooting (checked Nov 3, 2026)

Still stuck? Use the live chat on the panel or ask in the ESN Systems Discord. Last updated November 3, 2026.