Hello! I'm here to help you with the issue you're experiencing with the Libby app not responding on your Mac. Let's see if we can get you back to reading or listening as quickly as possible.

First, could you let me know if you've already tried any troubleshooting steps, like restarting the app or your Mac? This will help us avoid going over steps you've already completed.

Here are some initial things you can try:

1. Force Quit the App: Sometimes, simply closing the app completely can help. You can do this by going to the Apple menu in the top left corner, selecting “Force Quit,” choosing Libby, and then clicking “Force Quit.”

2. Restart Your Mac: After force quitting, it can be helpful to restart your Mac to clear any temporary issues causing the freeze.

3. Check for Updates: Make sure you have the latest version of the Libby app. You can check for updates in the App Store.

4. Check Storage Space: Ensure that your Mac has enough storage space available, as low storage can cause apps to respond poorly.

Please let me know what you've tried so far or if you need detailed instructions for any of these steps!