How do I diagnose a broken or conflicting mod/plugin?

When a mod or plugin breaks your server, the Console almost always names the culprit — the real skill is isolating which add-on is at fault. Here's a reliable way to narrow it down.

Reading the signs

The first error in your Console or latest.log usually names the offending add-on and points at a missing dependency or a conflict. From there it's a process of elimination.

Isolating the problem

1. Read the first error in the Console / latest.log — it usually names the add-on and a missing dependency or conflict.
2. Remove or update the named add-on and restart.
3. If you're unsure which one, remove half, test, and narrow down (or add them back one at a time).
4. Share the log via mclo.gs (the Console's "Share logs" button) if you'd like help.

Tip: A missing dependency — a library the mod needs — is a very common cause. Install the required companion mod and the error usually clears.

Frequently asked questions

Two add-ons are clashing — what do I do? Keep one, or find versions of both that are known to be compatible.

I'm having LuckPerms or login-plugin trouble — where do I look? Check that plugin's config and permissions; the Minecraft KB has specifics.