How to fix the – Cannot load VTK library – or – VTK unsatisfied link – error ?

Sometime you just need to add the bin directory of your JRE (Java Runtime Environment) in the PATH environment variable (instructions for Ubuntu here). If it still doesn’t work, you may try the following solutions:

• Unix / Linux: You may need to install VTK 8.0.1 library (with the java wrapper) by yourself depending your system distribution then add the installation path (ex : /usr/local/lib/vtk-8.0.1) to the LD_LIBRARY_PATH variable. Also  be sure to launch Icy from its installation folder (for instance by using the terminal, going to Icy installation folder and type ./icy or java -jar updater.jar)
• Windows 64: Sometime VTK 64 bit library is not loading correctly (work with java 32 bit), in this case you need to install the VC++ 2015-2019 redistributable to fix it.
• OSX: VTK is supported only for OSX > 10.7