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Tickwise
ErrorPluginsSIG-PL-001

Plugin not loaded: a required dependency is missing (UnknownDependencyException)

Platforms
Paper · Purpur · single server
Verified
Verified
Confidence
Confidence 97%

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
  • UnknownDependencyException: Unknownin the stack trace

Symptoms

  • The plugin is missing from /plugins (or shown in red) and its commands do not work
  • In the startup log: “Could not load '…' …” and UnknownDependencyException with a list of dependencies

Cause

The plugin's plugin.yml/paper-plugin.yml declares a required dependency (depend) that is not on the server or that failed to load itself, so Paper did not load the plugin.

Possible causes

  • The dependency (Vault, ProtocolLib, PlaceholderAPI, etc.) is not installed in plugins/
  • The dependency is installed but failed to load itself (look for its own error earlier in the log)
  • The dependency name does not match (a different fork/renamed plugin, e.g. VaultUnlocked instead of Vault)

How to fixLow risk

  1. Take the list in square brackets from the evidence — these are the missing plugins — along with the name of the plugin that needs them.
  2. Check whether these plugins are in plugins/ and whether they loaded (/plugins); if a dependency is present but did not load, fix its error earlier in the log first.
  3. Install the missing plugins from their official page (Hangar/Modrinth/SpigotMC), compatible with your server version, and restart the server (not /reload).

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

Sources