We got a new iMac for Christmas and it has seemed really slow for the past couple of days. In desperation I checked out Activity Monitor and it shows photoanalysisd as the guilty process that is hogging my CPU. I assume this is related to the Photos app, but that's not even running!

What is "photoanalysisd", why is it using 77% of my CPU, and can I safely stop the process?

  • No proof, but I'm guessing it's searching for faces in your photos. – JMY1000 Dec 30 '17 at 4:50
  • @JMY1000 Yes, this is one of the main things it’s doing. – Monomeeth Dec 30 '17 at 5:33

Your iMac is currently processing the photos in your Photos library, presumably because you’ve just imported/converted an existing Photos library from an earlier version of macOS.

If you suspect this has been the cause of your sluggishness for a couple of days, then it’s most likely you’ve got a very large photo library and that it’s being processed for the first time on your new iMac.

The fact that Photos isn’t running actually fits with your scenario, as launching the Photos app will pause the photoanalysisd daemon.

Although it takes a long time, once it’s finished your Photos app will be able to perform a lot of advanced functions due to all the metadata etc it’s processed, so I would let it finish what it’s doing.


Should you need to pause the process in order to free up some of your CPU, I would recommend just opening the Photos app for a while and then quitting it when you’re not using the computer. Note, however, that minimising the Photos app will act to restart the photoanalysisd daemon, so just leave it running in the background while you want to keep the daemon paused.

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    My photo library is 360GB in size, so it did take a long time, but all is working great now. Thanks! – user269919 Jan 1 '18 at 20:59
  • Opening Photos does not seem to pause photoanalysisd, whether in the background or foreground. It just leads to both photoanalysisd AND photolibraryd eating CPU. – David J Jan 18 '18 at 22:30
  • I see this running (via ssh on another account) when I'm trying to log in! It has been sitting here for 10 minutes not letting me log in and I see this stupid background process and wonder why I'm still not logged in!!! – Michael Jun 17 '18 at 5:59
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    Running Photos application has no effect in photoanalisysd for me, it's still taking most of the CPU... (macOS Mojave, 10.14.1) – Marinov Iván Nov 28 '18 at 13:04

Might I suggest the use of App Tamer?

It lets you pause/stop a process when it reaches a % of the processor time.

Since I use it, my computer temperature is always quite low.

Hope it helps!

P.S.: I am not affiliated at all with App Tamer. I am just a happy customer!


After photoanalysisd had been taking up 3 cores for over a month, I found a solution that reduced the CPU usage dramatically for me on High Sierra. I went into Photos and added names to some pictures - 4 pictures in total using 3 names. Photoanalysisd is currently using 0% whether or not Photos is open.

  • Just updated to Catalina. I had photoanalysisd taking 80% CPU all day, it only got through 900 photos. I followed this advice, named 5 faces it found, and now it's made 1600 scans in just an hour. Definitely add some names, if we can't get away from this feature, we can at least stop it from spinning. – Matt Stephenson Dec 4 at 1:09

I have only a dozen or so photos in my library (this is my spare computer, my photos are on my main computer) and I've let the process run for a week, and it is still eating up 100% of both cores. My machine is unresponsive with the CPU fan at 100% (13" MacBook Pro Mid-2010). None of the solutions I found on the web worked, I finally temporarily renamed my photo library to hide it from the deamon, and instantly had both CPUs go from 100% to around 5%.


That process interferes severely with time machine by hogging all available CPU. It is the only process that I encountered so far that is that annoying. Now I finally stop the process manually through Activity Monitor > select CPU > select "photoanalysisd" > click red stop sign in top left – as soon as it starts to interfere with my work. Not a permanent solution, but at least I can use my machine for what it is intended.

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