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Tickwise
ErrorPluginsSIG-PL-002

A file in plugins/ is not a plugin, or its plugin.yml is corrupted

Platforms
Paper · Purpur · single server
Verified
Verified
Confidence
Confidence 95%

What it looks like in the log

Any one of these lines is enough. The agent matches them locally, on your server.

logs/latest.log
  • Could not determine plugin type
  • Server jars do not belong in the plugin folder
  • [WARN] org.bukkit.plugin.InvalidDescriptionException: in the stack trace

Symptoms

  • A file in plugins/ does not show up in /plugins
  • In the startup log: “does not contain a paper-plugin.yml or plugin.yml”, “appears to be a server jar” or InvalidDescriptionException

Cause

Paper could not recognise a file in plugins/ as a plugin: the jar has no plugin.yml/paper-plugin.yml (a Fabric/Forge mod, a library, a server jar) or plugin.yml is invalid.

Possible causes

  • A Fabric/Forge/NeoForge mod or a client-side mod was put into plugins/ — it does not work on Paper
  • plugins/ contains a library/dependency or a server jar rather than a plugin
  • plugin.yml is corrupted or lacks required fields (name/version/main) — a broken or incomplete download

How to fixLow risk

  1. Find the file name and the reason in the evidence: “does not contain a paper-plugin.yml or plugin.yml” — not a plugin; “appears to be a server jar” — a server jar; InvalidDescriptionException: … — plugin.yml is corrupted.
  2. Remove Fabric/Forge mods and server jars from plugins/ (mods need a different platform or an equivalent plugin).
  3. If it is a plugin you need, download it again from the official page (the file may have been downloaded incompletely) and check that the version is meant for Paper/Spigot.
  4. Restart the server.

Translated from the Russian original; log lines are quoted verbatim.

Sources