Another way to resolve the problem : Click the left mouse's button on the project folder in the project structure at the left, and click on "open module settings" in the list of actions In the new windows, click on SDKs which is under the menu title "Platform settngs" Then check on the "Classpath" list if you can find the jfxrt plugin path, if not, click on the + symbol on the right and select the repertory of the jfxrt plugin (C:\Program Files\Java\jdk1.8.0\jre\lib\ext\jfxrt.jar on my desktop)