If you have an PlayStation 4 and have noticed that your disc is not recognized, there are a few things you can do to fix it. The first step is to check if the disc is actually defective. If it is, you can replace it with a new one or try to fix it yourself. If the disc is not defective, the next step is to look for any clues that might tell you what might be wrong with it. One clue might be if your PlayStation 4 has been experiencing problems with its graphics or sound. If your PlayStation 4 has not been behaving as expected, then you may want to take it in for service. The last step before trying to fix the disc yourself is to make sure that you have the correct tools and knowledge for the task at hand. If you do not have these tools or know how to use them, then you may want to seek out help from a professional who can help you fix your Playstation 4.