Hi there! I understand your BorrowBox app on your Mac with OS X 10.15.7 isn’t playing audiobooks. Let’s see if we can get that sorted out.

First, can you tell me a bit more about the issue?
- Is the app launching fine?
- Does the audiobook start playing and then stops or just won’t play at all when you hit play?
- Are you connected to the internet when you try to play?

Meanwhile, here’s a step-by-step you can try on your Mac that often helps resolve playback issues:

1. Force Quit and Reopen BorrowBox
- Click on the Apple menu (top-left corner), select “Force Quit...”, choose BorrowBox, and click “Force Quit.”
- Then reopen the app.

2. Check for Updates
- Since you're using OS X 10.15.7, make sure your BorrowBox app is the latest version for macOS. Updates often fix bugs tied to audio playback.

3. Restart Your Mac
- A quick restart can clear temporary glitches affecting audio.

4. Log Out and Log Back In
- In BorrowBox, log out of your account and then back in. Sometimes, that refreshes the connection with the servers and fixes playback.

5. Clear Cache or Temporary Files (if possible)
- Though not always accessible on Mac apps, look for any option in settings related to cache or downloads and clear them.

6. Check Audio Output
- Use the Mac’s sound settings to make sure output is going to your speakers or headphones correctly. Sometimes the app plays but sound routes elsewhere.

7. Re-download the Audiobook
- Delete the downloaded audiobook file and download it again to ensure the file isn’t corrupted.

If after trying these steps, BorrowBox still won’t play audiobooks, it could be related to a more specific issue with the app or account. There have been reports of app versions needing updates for audiobook playback fixes on Apple devices1 2.

Go ahead and try these steps and let me know how it goes. If needed, I can guide you through some more advanced troubleshooting! Are you able to reproduce the problem right now?