Direct answer
Mod dependency errors mean a required mod or compatible version is missing. Match the exact Minecraft release, Fabric/Forge/NeoForge loader and each required library; do not substitute a plugin JAR.
Recommended procedure
- Read the first useful error in the mod-loader startup log. Note the requesting mod, the missing dependency identifier and the required version range.
- Check the mod’s download page and dependency list. Record whether each library is required on the dedicated server, client, or both.
- Download the dependency build specifically published for the target Minecraft release and mod loader. A Fabric API release does not substitute for a Forge or NeoForge library.
- Put server-compatible JARs in the server’s
mods/folder; keep client-only mods off a dedicated server unless authors explicitly support that use. - Restart and resolve the next reported missing or conflicting requirement. If two mods require incompatible ranges, find supported releases instead of overriding metadata blindly.
Why this matters
Dependency failures may be caused by a wrong version even when the dependency file exists. A client-only class loading crash is a different problem and must be diagnosed separately.
How to verify the result
- Confirm the loader identifies the intended mod list without missing dependency errors.
- Connect using a compatible client pack where required and test representative modded content.
- For a modpack update, roll back server mods, configs and world data as a matched set if an incompatible change affected registries.
Version and compatibility notes
Important
Fabric documentation warns against dependency overrides for ordinary users. They can bypass validation without making incompatible code work.
Official references
Related guides
Help us improve this article
Tell us what is missing, unclear, outdated, or incorrect. You can also suggest something we should add.