mds and mds_stores are constant CPU consumers even when I think nothing should have changed on the hard drive.

Activity Monitor:

activity monitor

I have a circa 2009 Macbook Pro. Lots of software installed over the years. Dropbox and Crashplan are active background process among many others.

I have included many locations in the privacy settings of Spotlight.

  • USB drive
  • Crashplan folder
  • /Library/Caches
  • /Users/me/Library/Caches

Still, mds and mds_stores are constant consumers of CPU hovering around 10-12% each. My fan keeps running due to the heat.

Any ideas as to what it could be due and how I can troubleshoot?


As you know, the mds and mds_stores are Spotlight activities.

The reason why your Spotlight is so active could be a number of things; it could be you have an app or multiple apps constantly changing some folder contents.

First let's check whether Spotlight is the cause of the fans running so much. To test this, run the following in your terminal:

sudo mdutil -a -i off

this turns off indexing of files, and should result in a clear slow down of the fans if mds and/or mds_stores are to blame.

To turn indexing back on, run

sudo mdutil -a -i on

After this you could run the complete re-indexing of your hard drive (be aware this could be an over night job), it will delete your Spotlight data base forcing it to start over.

sudo rm -rf /.Spotlight-V100/*

The next and final step would be to add others to your (do not scan), privacy settings.

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  • 1
    To add to this for me the culprit was cloud sync folders like dropbox and drive alongside a local database, removing those from the search path solved it for me – mapping dom Nov 22 '19 at 8:21
  • Ah ok, so if it's indexing than that explains it after I just migrated my TimeMachine on my new laptop. – Ansjovis86 Feb 22 at 5:32

Just to add a small tip on top of @Buscar웃 's correct answer: In my case, I realized that spotlight was actually indexing Time Machine backups (which is really a stupid thing to do in the first place). To me, this explains the constant CPU in the first place - TimeMachine creates an hourly backup, Spotlight tries to index it... After stopping the indexing service and removing existing indexes as indicated above, and before re-starting the indexing, I also excluded the TimeMachine volumes (open finder, go --> go to folder --> /Volumes, and then drag the TimeMachine volume to the exclude list of Spotlight). Fingers crossed.

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  • Doesn't work for me in MacOS 10.15.3. I get this message '"Volume Name” is a Time Machine backup folder. You cannot add it to the privacy list.' – Jayden Lawson Feb 26 at 23:32

I got the same issue, almost bought me a new mac. I checked all the stuff on the net about mds_stores etc... All I got was terminal programming and clean installation solutions.. without guarantees of fixing the problem.

So I checked my free-to-download cleaning and maintenance tool "Onyx" and in the navigation bar under maintenance you can check "Spotlight Rebuild" (as default is unchecked).

After that I had no problems and speed was up to normal. Also, Activity Monitor stays within normal parameters. I hope it stays that way and works. For it is an easy and free tip for non-technical Mac users.

Found that out an hour ago but looks promising. Goodluck

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I had this same issue. I went into Security & Privacy System Preference, just to look at what Spotlight was including. I checked one thing off and then back on again and it immediately stopped. Mine was using almost 100% CPU power and my fans were running nonstop. It all stopped after I did this and I have no idea why. I have a Mid 2012 MacBook Pro.

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After trying everything there is on the web and forums, and nothing worked - a smart guy (Lincoln Adams) on the Apple forum with the same issue, made a mind blowing discovery: In his case (and mine, and maybe yours) - this was caused by the Pinterest button/extension in Firefox. Try closing Firefox, rebooting, and using another browser for a while. The thread on Apple forums

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if figured out when running the command sudo mdutil -a -i off that spotlight is trying to index a USB connected drive of one Terabyte. I disconnected it and restarted the computer.

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I had this problem and it persisted even after disabling spotlight search. ALthough I don’t have the pinterest extension mentioned above, I found that closing Firefox solved the issue.

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You said, "I have included many locations in the privacy settings of spotlight."
You need to include FEWER locations, not more. If you include more, that means Spotlight is keeping very busy looking at them all.
You can easily go to System Preferences/Spotlight to un-select many locations. Especially, un-select Mail, search engines, and other internet dependent options.
Shut down and restart after changing your Spotlight preferences.

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    You are mistaken, in fact you have it back to front, the privacy panel of Spotlight says, and I quote: "Prevent Spotlight from searching these locations" so having fewer locations in privacy will actually cause spotlight to keep BUSIER. Having more locations unchecked in the Search Results panel will do as you say but the more you put in the privacy panel the less spotlight will search. – sdjuan Oct 6 '16 at 4:25
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    Yes, this is actually quite bad advice. Anything you don't want scanned should be in Privacy. – Joe McMahon Jan 26 '17 at 17:16

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