Hi! I understand your FreeCell Solitaire app is crashing about 20 seconds after you start playing. Let's see if we can get you back to enjoying your game smoothly.

First, just to make sure, could you tell me:
- When did this issue start happening?
- Have you recently updated your macOS or the FreeCell Solitaire app?
- Have you tried restarting your Mac or the app so far?

Meanwhile, let's go through a few steps that often resolve this kind of crash on your Mac (OS X 10.15.7):

1. Restart Your Mac: This clears temporary memory issues that can cause apps to crash.
2. Check for App Updates: Open the app store and ensure your FreeCell Solitaire app is the latest version.
3. Close Other Apps: Sometimes running many apps at once can cause memory shortage. Quit apps you're not using.
4. Free Up Space: Make sure you have at least a couple of gigabytes of free disk space on your Mac, as low storage can lead to crashes.
5. Reinstall the App: If the problem persists, try deleting the app and reinstalling it to fix possible corrupted files.

If these do not help, we can also look into if any other background software conflicts with the game, or if there may be corrupted system files causing the issue.

Let me know which steps you’ve taken or if you need help with any of them!