KNIME 4.4.0 Windows Possible Bug with Loading MOE Nodes

I am experiencing a persistent error concerning the MOE KNIME nodes in Windows 10. After installing MOE 2020.0901 for Windows, KNIME 4.4.0 for Windows, and the MOE KNIME nodes, when I start KNIME, I get the following error:


An internal error occurred during: “Workflow Coach loader”.


After clicking “OK” on the error window and looking at the node repository pane in the KNIME interface, I see that only some of the MOE nodes have been loaded.

In the .log file for KNIME, there is an issue that mentions the MOE KNIME nodes:


!ENTRY 4 2 2021-07-05 11:40:28.436
!MESSAGE An internal error occurred during: “Workflow Coach loader”.
java.lang.NoClassDefFoundError: org/knime/node/v212/KnimeNodeDocument$Factory
at com.chemcomp.dynamic.MoeNodeFactory.createNodeDescription(
at org.knime.core.node.NodeFactory.init(
at org.knime.core.node.NodeFactory.loadAdditionalFactorySettings(
at com.chemcomp.dynamic.MoeNodeFactory.loadAdditionalFactorySettings(
at org.knime.core.node.extension.NodeSetFactoryExtension.createNodeFactory(
at org.knime.workbench.repository.RepositoryFactory.createNodeSet(
at org.knime.workbench.repository.RepositoryManager.readNodeSets(
at org.knime.workbench.repository.RepositoryManager.readRepository(
at org.knime.workbench.repository.RepositoryManager.getRoot(
at org.knime.workbench.repository.RepositoryManager.getRoot(
at org.knime.workbench.workflowcoach.ui.WorkflowCoachView$
Caused by: java.lang.ClassNotFoundException: org.knime.node.v212.KnimeNodeDocument$Factory cannot be found by com.chemcomp_2.4.4.20210128
at org.eclipse.osgi.internal.loader.BundleLoader.findClass(
at org.eclipse.osgi.internal.loader.ModuleClassLoader.loadClass(
at java.base/java.lang.ClassLoader.loadClass(Unknown Source)
… 12 more



  1. I got the same behavior previously when using Oracle Java. I uninstalled Java, MOE, and KNIME, then installed Microsoft OpenJDK, reinstalled MOE, and reinstalled KNIME, but I got the errors shown above.

  2. My Linux installation of MOE and KNIME is working properly. However, I am still using KNIME 4.3.3 for Linux; I haven’t yet updated to KNIME 4.4.0 for Linux.

  3. I uninstalled KNIME 4.4.0 for Windows and installed KNIME 4.3.3 for Windows. After reconfiguring the MOE nodes, this version of KNIME works as expected. Therefore, it seems that the problem was with KNIME 4.4.0 rather than with MOE.

Thanks for your help with this.

Hi. I’m planning to update our KNIME server soon to either 4.12 or 4.13, and we use MOE. This post makes me think 4.12 would be preferred to avoid this bug?

I do not know what to advise regarding KNIME server.

I did receive a reply today from CCG MOE tech support. They confirmed that the MOE nodes are incompatible with the new code that has been implemented in KNIME 4.4.0. They also said that they are working on recompiling the MOE nodes but that they might not be releasing the new ones until sometime in August or so. Their recommendation was to continue using KNIME 4.3.3 if I wanted to use the currently available MOE nodes.

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Thanks, @rjrich , that’s definitely good to know.

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