We're sorry about the trouble with Lightroom Classic. Would you mind telling us the images are located on your computers local storage or an external drive?
Please ensure that Lightroom Classic has the necessary permissions on your Mac using the steps mentioned below:
1. Go to the System Preferences for your Mac, then Security and Privacy, then select the Privacy tab.
2. Then select Accessibility from the list to the left & check if Photoshop is added to the list with a check mark in front of it.
3. If Photoshop is not a part of the list, please add it by unlocking the window first using the lock at the bottom left, then clicking the + icon & navigating to the Applications folder.
4. Also, grant permissions to Photoshop under Full disk access located in the same list as Accessibility.
5. Once done, restart the Mac & check if it helps.
You can also check out: https://helpx.adobe.com/lightroom-classic/help/locate-missing-photos.html
Lets us know if it helps!