Fail to instantiate module “vtkvmtk” error reported at startup

[lassoan]

This error is reported at Slicer startup if SlicerVMTK extension is installed:

CLI executable: C:/Users/E/AppData/Roaming/NA-MIC/Extensions-29387/SlicerVMTK/lib/Slicer-4.11/qt-loadable-modules/vtkvmtk.py
The process failed to start. Either the invoked program is missing, or you may have insufficient permissions to invoke the program.
Fail to instantiate module “vtkvmtk”
The following modules failed to be instantiated:
vtkvmtk

[lassoan]

This error message can be safely ignored.

It is due to that vtkvmtk.py gets installed in the module folder where Slicer tries to interpret it as a Slicer module, while it is not.

The error message is harmless but still confusing for users, so it should be fixed.

[lassoan]

An error message also appears in the module finder if a user tries to find the non-existing "vtkvmtk" module:

(source: https://discourse.slicer.org/t/help-request-extension-fails-to-load-after-installation/42008/2)