photoanalysisd

Analyzing a large library takes time and processing power. It can run for hours, or across several sessions, on a big library.

The simplest approach is to leave the Mac on, connected to power, and not busy with other work, so the analysis can complete. Quitting photoanalysisd only pauses the work, and it resumes later.

You can follow its progress in Activity Monitor instead of guessing. Normal looks like a busy period after new photos arrive, followed by long quiet stretches. A worrying pattern is photoanalysisd staying busy for days while you have not added anything to the library.

You do not need to keep the Photos app open for this. photoanalysisd is a background agent, so it keeps working after you quit Photos, and it picks up again after a restart.

1. Open Activity Monitor and type photo in the search field. You will see photoanalysisd and possibly photolibraryd and cloudphotod.
2. Click the CPU tab and watch photoanalysisd's % CPU for a minute. Steady use means it is analyzing photos.
3. Click the Energy tab to see its Energy Impact compared with your other apps, which matters most on a laptop running on battery.
4. Check again after a few hours. If its CPU use has dropped and stays low, the analysis is done or nearly done.

photoanalysisd is one of several background processes that support the Photos app. Knowing which is which tells you what kind of work is going on.

• photolibraryd: the photo library agent, which handles requests to the library.
• cloudphotod: the iCloud Photos agent, responsible for iCloud Photos activity such as uploads and downloads.
• photoanalysisd: the analysis agent for Memories, People and search by scene or object.

No. Apple says face recognition and scene analysis in Photos are done on your device, and that the results of that analysis are not shared with anyone, including Apple. That on-device work is why it uses your Mac's CPU instead of happening in the cloud.

If you use iCloud Photos, your photos themselves are stored in iCloud, and cloudphotod handles that syncing. That is separate from what photoanalysisd does.

The two often run together, though. When you turn on iCloud Photos on a new Mac, cloudphotod downloads your library and photoanalysisd analyzes what arrives, so both can stay busy until the download is complete.

Do not turn iCloud Photos off just to quiet photoanalysisd. The analysis runs on the library stored on your Mac either way, and turning iCloud Photos back on later can mean a large download all over again.

Do not delete files inside your Photos library or in system folders to stop the analysis. You can damage the library, and the analysis would start over later anyway. If Photos itself misbehaves, Apple has a Repair Library tool for that.

If photoanalysisd stays busy for days with no new photos, restart the Mac first. If that does not help and Photos also shows problems, back up the library, then quit Photos and hold down Command and Option while you open it. In the window that appears, click Repair. The repair can take a while on a large library.