Whoops

Only update the OpenFileHandler if you're on macOS

swing/src/net/sf/openrocket/startup/SwingStartup.java

@@ -216,7 +216,9 @@ public class SwingStartup {
 		Databases.fakeMethod();
 
 		// Set up the OSX file open handler here so that it can handle files that are opened when OR is not yet running.
-		OSXSetup.setupOSXOpenFileHandler();
+		if (SystemInfo.getPlatform() == Platform.MAC_OS) {
+			OSXSetup.setupOSXOpenFileHandler();
+		}
 		
 		// Starting action (load files or open new document)
 		log.info("Opening main application window");