Fix mds_stores on Mac Using Excess Memory & CPU
Some Mac users may discover the mds_stores process has run amuck, consuming absurd amounts of CPU and memory when viewed in Activity Monitor. Typically this is accompanied by unusually sluggish system performance on a Mac, which is what inspired the visit into Activity Monitor to begin with, and there you may find that mds_stores is taking up 100% or more CPU, and perhaps many GB of RAM to the extent that it’s causing significant swapping and virtual memory usage.
Let’s dig into mds_stores to learn about what it is, what it’s doing, and more importantly to the topic on hand, how to fix it when it has gone haywire and is consuming large amounts of system resources including CPU and memory.
What is mds_stores?
mds_stores is one of the core background processes for the Spotlight search feature and it’s associated indexing database on a Mac. mds_stores will run in the background and catalog files, apps, changes, metadata, media, and file contents, so that Spotlight search results behave as expected and offer quick results.
The mds_stores process is always running in the background on a Mac so that the Spotlight search database is always updated, but occasionally it can go haywire and consume an inordinate amount of CPU and/or memory, which can cause a Mac to run slow, or become physically hot to the touch.
In the example screenshot here, mds_stores has suddenly taken up 12GB of physical memory, swapped 20GB of virtual memory, is taking up 100% CPU, and has dragged an M-series Mac performance down to molasses. Annoying, but there’s a pretty simple solution.
How to Fix mds_stores Taking Up Large CPU & Memory Usage on Mac
First, remember that mds_stores is running because it is indexing a Mac. Therefore it’s generally best to let that indexing finish, after which the mds_stores process should return back to normal resource usage. If mds_stores resource usage is extreme and you want to intervene, here’s what to do:
Best Approach: Restart
The cleanest way to handle an errant mds_stores process is to restart the Mac. A restart is most effective because it will gracefully exit the process (and associated processes too), dump caches, and then retrigger the indexing process again once the Mac has restarted successfully.
- Go to the Apple menu and choose “Restart”
Rebooting can be annoying because it might interrupt your workflow, but so does an errant process that is consuming all of your available system resources and dragging down your Mac performance.
Oh, and if you have not updated MacOS system software in a while, you should do that too. If there is a well known performance bug in Spotlight, it will likely be fixed in a software update.
Quick Temporary Approach: Kill the mds_stores Process
If you can’t immediately reboot, a temporary solution of targeting the process can give you a quick temporary fix. You can force quit the mds_stores process to end it’s massive consumption of CPU and memory, but be aware this is really just a temporary solution because the mds_stores process will eventually start back up again on its own, and often the underlying issue is not resolved and so you might experience a quick return to mds_stores going hayware and slowly consuming more memory again.
- From Activity Monitor, search for “mds_stores”, select it, and then click the (X) button in the toolbar
- Confirm that you want to force quit the process, and authenticate with an admin account
- Now go to the Finder, Finder menu > Finder Settings > Advanced > toggle “Show file name extensions” OFF and wait a few seconds, then toggle it back ON again, this trick actually restarts Spotlight gracefully
At this point it’s good practice to wrap up whatever you are currently working on, save any data, quit out of apps, and then restart the Mac anyway. Anytime some process has gone completely haywire and has consumed so much RAM that it’s aggressively swapping onto disk, or melting your CPU, often the simplest and cleanest real solution to that is to restart the Mac.
What not to do: use Terminal to turn Spotlight off and on, avoid rebooting
You will find a lot of regurgitated “advice” from non-experts online that suggest to use the Terminal to recite an incantation and burn incense during a full moon while turning Spotlight off and then back on again targeted at some specific directory path, but this almost never actually resolves the problem with Spotlight consuming too much CPU or memory. It might temporarily, similar to the approach of killing the mds_stores process outlined above, but the fix is temporary (if at all), and since most Mac users are not comfortable in the Terminal, it can often get them into more trouble than they started with. Ultimately the best thing to do is to restart the Mac.
If you want to try toggling Spotlight off and on, you can use this trick of toggling file extensions off and on to restart Spotlight on the Mac, which is much more graceful and user friendly than going into Terminal and mucking around with disk paths, which has a high chance of making something worse for a casual user.
Why does this happen?
Spotlight performs a lot of functions on modern Macs, and indexing happens in the background periodically to keep everything working smoothly. While this usually works great and without notice by the user, sometimes indexing and background tasks do not go smoothly, and whether that be due to a bug in Spotlight, macOS, an incompatibility with a third party app, or a completely idiopathic Spotlight issue, the good news is that fixing the problem is usually pretty straight forward.
Troubleshooting mds_worker and Spotlight in general might be annoying, but if you’re a longtime Mac user this probably isn’t your first Spotlight troubleshooting rodeo. The reality is that issues with mds and related mds processes have been around forever going back to the early days of Spotlight on the Mac, and while it’s an incredibly powerful search engine for the Mac that generally performs very well, the latest versions of Spotlight on MacOS with more and more features seem to be more prone to random problems, hiccups, memory leaks, and errant CPU issues. This isn’t too surprising because Spotlight is no longer just a simple search engine on the Mac, it has now transitioned (potentially over-engineered) into a Launchpad replacement, a clipboard manager, an action launcher, file browser, app launcher, and so much more than just a file search engine.
Have you ever had a problem with mds_worker running amuck and consuming lots of CPU or memory on your Mac? Did you fix it with a simple reboot, or did you track down another specific solution that worked for you?
