java.lang.AssertionError: If valid, it should be a folder: C:\Users\jcramer\Documents\NetBeansProjects\AlchimieJFX\build\classes\alchimie@5bc89128:c82be5
   at org.netbeans.modules.masterfs.watcher.Watcher$Ext.unregister(Watcher.java:248)
   at org.netbeans.modules.masterfs.watcher.Watcher.unregister(Watcher.java:127)
   at org.netbeans.modules.masterfs.filebasedfs.fileobjects.BaseFileObj.removeFileChangeListener(BaseFileObj.java:519)
   at org.openide.filesystems.FileUtil$Holder.run(FileUtil.java:583)
   at org.openide.util.lookup.implspi.ActiveQueue$Daemon.run(ActiveQueue.java:185)