Error Codes › Missing or unsupported mandatory dependencies

Missing or unsupported mandatory dependencies

COAL-006 · Missing mod dependency

A Forge or NeoForge mod needs another mod that is not installed, or is installed at the wrong version. How to read the dependency table and fix every row.

What it looks like in the log

Missing or unsupported mandatory dependencies:
	Mod ID: 'jei', Requested by: 'somemod', Expected range: '[15.2,)', Actual version: '[MISSING]'

What it means

Mods declare what they need. This message is the loader listing the requirements it could not satisfy, and it is unusually helpful: each row names the mod that is missing (Mod ID), the mod that wants it (Requested by), the version range that would work (Expected range), and what is actually installed (Actual version, where [MISSING] means nothing at all).

How to fix it

If Actual version is [MISSING], install the named mod. Search the Mod ID on Modrinth or CurseForge and take the build for your exact Minecraft version and loader.
If a version is listed but out of range, you have the right mod at the wrong version - update or downgrade it into the expected range.
Or remove the requesting mod if you do not actually want it. The Requested by column tells you which one to pull.
Fix every row before restarting. The list is complete, so there is no reason to discover the next one on the next boot.

The Fabric equivalent of this message is COAL-019.