After updating Matrix Project Plugin Jenkins fails to restart.

Article ID:204170674
1 minute readKnowledge base


  • The Jenkins instance is returning error 500 after some plugins upgrade. The error shows that the class hudson/matrix/MatrixProject is missing.

  • The following plugins are deactivated because of cyclic dependencies, most likely you can resolve the issue by updating these to a newer version.

    • windows-slaves

    • matrix-auth

    • matrix-project

    • antisamy-markup-formatter

    • script-security

  • SEVERE: found cycle in plugin dependencies: (root=Plugin:matrix-auth, deactivating all involved) Plugin:matrix-auth -> Plugin:windows-slaves -> Plugin:antisamy-markup-formatter -> Plugin:matrix-project -> Plugin:script-security -> Plugin:matrix-auth

  • Caused by: com.thoughtworks.xstream.mapper.CannotResolveClassException:


  • Jenkins LTS < 1.596.1

  • Jenkins < 1.600

  • matrix-project 1.4.1


If you have hit this error, it means that you are running an obsolete version of Jenkins core which has an Advisory.

Resolution to this issue is to upgrade Jenkins core to 1.600+ for non-LTS line, and 1.596.1+ for the LTS line.

Workaround, Matrix Project Plugin is incompatible with Jenkins LTS < 1.596.1 and Jenkins < 1.600 (see Release Notes). To restore you instance, revert your upgrade:

  • Stop Jenkins

  • In $JENKINS_HOME/plugins/ replace matrix-project.jpi by matrix-project.jpi

  • Restart Jenkins