I decided to create a new post since my old one was on the 2019 version. I've been having this problem for over 6 months now, and this only happens on this certain computer. On another computer I tested, it renders fine. I'm unable to render swf files, once it gets to 50% it either completely closes or says "Not Responding". I tried reinstalling the application, using 2018, 2019, and now 2020. I feel like this might have something to do with Java, but am unsure.
Apologize for your experience and thank you for being patient with the troubleshooting. If you are still facing this issue, I suggest getting in touch with our tech support team using this link https://adobe.ly/2WYE62m Use the chat button to get started. Let them know of all the troubleshooting you have done thus far.