For an unknown reason, Photos recently merged all the photos of my wife & daughter into one profile. There are almost 10,000 photos between the two of them, and it would take forever to go through them to separate them out.
Is there a way to reset each person and relearn their faces?
MacBook Pro (2017 – 2020)
If you are not using iCloud Photos, you could try to restore the Photos Library from the last backup you made before the two people albums got merged. If you have been using iCloud Photos, you would have to erase iCloud Photos as well before restoring the library from your backup. However, the backup may be incomplete, if "optimize Mac Storage" has been enabled.
In that case you must not erase the iCloud Photos Library, as it may be holding the only copy of some of your photos.
To force Photos to reset the face recognition for your wife and your daughter, select all photos in the album of your wife with ⌘A, then use the command "This is not ...", so the album will be empty. Foo the same for the album of your daughter. Wait, until this changes have been updated in iCloud Photos on all your devices, if you are using iCloud Photos.
Now give Photos time to run the face recognition again.
Then you can again add names to the faces, but do not use the names from the contacts card of your wife and daughter. use two new nicknames, that never have been used with Photos, or the faces might be merged again. You can switch back to the correct names, once the two sets of faces have been properly separated.
See: How to Correct Merged People Albums - Apple Community
If you are not using iCloud Photos, you could try to restore the Photos Library from the last backup you made before the two people albums got merged. If you have been using iCloud Photos, you would have to erase iCloud Photos as well before restoring the library from your backup. However, the backup may be incomplete, if "optimize Mac Storage" has been enabled.
In that case you must not erase the iCloud Photos Library, as it may be holding the only copy of some of your photos.
To force Photos to reset the face recognition for your wife and your daughter, select all photos in the album of your wife with ⌘A, then use the command "This is not ...", so the album will be empty. Foo the same for the album of your daughter. Wait, until this changes have been updated in iCloud Photos on all your devices, if you are using iCloud Photos.
Now give Photos time to run the face recognition again.
Then you can again add names to the faces, but do not use the names from the contacts card of your wife and daughter. use two new nicknames, that never have been used with Photos, or the faces might be merged again. You can switch back to the correct names, once the two sets of faces have been properly separated.
See: How to Correct Merged People Albums - Apple Community
Reset People & Pets in Photos
