What photoanalysisd does
Photos can find pictures by who or what is in them. That requires examining each image once and storing what it found. photoanalysisd is the background process that does the examining.
It is deliberately patient. macOS schedules it when the Mac is idle and on power, and backs it off when you are working. A laptop used all day on battery can therefore take a long time to finish.
When high CPU is expected
You recently imported a lot of photos, migrated to a new Mac, signed in to iCloud Photos, or installed a macOS update, and the load changes between readings.
A first pass over a large library is real work and can occupy a processor core for a long stretch. How long depends on the number of images, whether they are stored locally, and how often you interrupt it by using the Mac.
Fixleave the Mac awake and on power, and let a first pass finish. Closing Photos does not stop the analysis; it runs independently of the app being open.
Signs the analysis is not finishing
The same load returns for weeks with no import to explain it, or the process climbs again within seconds of every wake.
That pattern can point to one unreadable image, a library that was interrupted mid-rebuild, or a sync that keeps re-delivering the same files. Processor use alone cannot tell those apart. What separates them is whether the Mac is ever idle on power long enough to work, and whether the same failure repeats in the logs.
What Noah can determine on this Mac
NoahNoah can take a reading of photoanalysisd, check how long this Mac has been up, and read recent logs for the same failure repeating. A repeating failure is the signal that separates a long first pass from analysis that never finishes.
Each reading is a single snapshot, not a recording, so the comparison over time is still yours to make. Noah cannot read what Photos reports about its own library either. It will not call a library corrupt from one hot reading, or predict when analysis will end.
Safe manual checks
- Ignore the status line at the bottom of the Photos library when judging this. Apple documents it as iCloud sync status, not analysis progress, and the two are easy to confuse.
- In Activity Monitor, search for
photo. Note the value, then check again after an hour rather than acting on one sample. - Connect power and leave the Mac awake without using it. The analysis is scheduled for exactly that condition.
- If the library was recently copied or restored from a backup, expect a full first pass rather than an incremental one.