MacOS Photos not recognizing faces

Actually I have similar troubles here like you mentioned esrlier in your message.

the apo was for whatever readon micing up two contacts with a single person in my photos app. When I tried to tell the app that this is not the person which it claimed to be, all selected photos got somehow removed from the recognition in general (at least that is how it appears to me) when nacigating manually to the respective images, no face is recognised. Super sad to lose all these valuable search functions for a really important friend of mine 😔

Hello craigmoor,

Thank you for using Apple Support Communities. We want to help you with the Photos. If the Photos app isn't identifying people correctly, you can manually update that information by following these steps here: Find and identify photos of people in Photos on Mac - Apple Support

Manually identify and name people in a photo

Some photos may contain people who are not automatically named. You can name them manually.

1. In the Photos app  on your Mac, double-click a photo to open it.

2. Do one of the following:

* Choose View > Show Face Names. Click the name (or click “unnamed”) under a face, type a name, then press Return (or choose a name that appears as you type).

* Click the Info button  in the toolbar. Click the Add button , drag the circle to position it over the face if necessary, click the Name field, type a name, then press Return.

* You can click the Add button  multiple times to identify multiple faces in a photo. To remove a name that you added to a face, click the Remove button  on the person.

To stop showing face names in photos, choose View > Hide Face Names.

If manually updating doesn't help out, try these additional steps below:

1.) Install pending macOS updates. Updates include fixes: Update macOS on Mac - Apple Support

2.) If you're fully updated, test in safe mode: How to use safe mode on your Mac - Apple Support

Thank you for using Apple Support Communities. Take care.

Photos is scanning each photo only once faces, when we first add it to the library. only when we add adjustments to a photo or upgrade Photos to a new version with an improved face detection, Photos will scan the photos again.

There are two possible reasons for missing recognized faces:

• Perhaps the process to analyze the library has crashed. Have you occasionally restarted you Mac and Photos, to ensure that all background processes are up and running?
• Or Photos has misclassified the faces and erraniousely addd them to the album of a different person. Have you looked into all People albums, if there are wrong photos in the in some of them?

Which system version is installed on your Mac? If your Mac os running macOS 10.15 Catalina or newer, you may be having items in your Photos Library that can no longer be scanned by Photos, for example old videos in a legacy format. Such legacy items can block the scan for Faces. You may want to try to identify the some of the items where Photos could not find any faces and check the format. A list of potentially problematic image nad video formats is here: About legacy media in iMovie for macOS - Apple Support

This doesn't work for me either. Photos was automatically identifying and suggesting faces but hasn't done so in months.