I tried all the above and nothing seemed to work. I am working with Notepad++ version 8.8.3 and originally i had the configuration file name config.model.xml. What actually worked for me was to first uninstall the app and removed all the remaining files. then i rebooted to clean up any remained. then i reinstalled the app and got a copy of the configuration file name config.xml and replace it and that fixed the issue. i also compared both configuration files config.model.xml and config.xml and the model was does not have the correct configuration, so this is why the recommendations of adding and removing config lines did not work .