Question: I don't like the feature that automatically detects faces in Photos for OS X because of the unnecessary CPU and disk space consumption. A photo library of 360 MB generated 50 MB of face detection data inside the Photos Library.

Is there any way to disable this feature in Photos for OS X?

Answer: 
Apparently you can stop face recognition by quitting iPhotos, opening a terminal and typing the following (and press enter):

```
defaults write com.apple.iPhoto PKFaceDetectionEnabled 0

```

I guess you'll then need to manually delete all the faces it's recognised thus far.

As for the new "Photos" app, I don't think you can disable the face detection.
There is a way to do this now in Photos Version 3.0 (3271.13.150).

In the sidebar select People. Then select all the faces that show up and right click. There is an option to delete/reset all saved face data.