There is a known issue with the FaCT++ reasoner for Protégé 5.5.0 on Windows. Fortunately a solution has been posted on http://protege-project.136.n4.nabble.com/Protege-5-5-0-and-Fact-td4671904.html.
- Ensure that "Microsoft Visual C++ Redistributable for Visual Studio" is installed.
- Download OpenJDK and extract the zip file.
- Download the FaCT++ plugin and save it in the Protégé plugin directory.
- Download the fix to the same directory.
- Open a command window in the plugin directory and run
/path/to/jdk-13.0.1/bin/jar umf factplusplus-P5.x-v1.6.5-manifest-fix-win10.txt uk.ac.manchester.cs.owl.factplusplus-P5.x-v1.6.5.jar
- Open Protégé and check that FaCT++ can be found under the Reasoner menu.