Board Thread:Questions and Answers/@comment-2605:6000:5745:1A00:31B4:3313:F52B:8FA0-20170826232507/@comment-65.27.147.71-20170827195416

If it has a .jar at the end of it then remove that part from its name, if it doesnt then add the .jar to the end. I can't remember which one I did because it was a long time ago that this happened for me. Also make sure that you have the correct Forge Version installed because that can cause problems to if you have a forge version thats older than the whats required