What is mds_stores?
mds_stores manages Spotlight's index: the database that makes searching your Mac instant. Together with mds and the mdworker_shared processes, it reads new and changed files and records their names, contents and details so you can find them later.
When a lot changes at once, Spotlight has a lot of catching up to do, and mds_stores can use plenty of CPU and disk for a while.
Why is mds_stores using so much CPU?
- After a macOS update, when Spotlight often rebuilds part of its index.
- A new or newly connected drive, which Spotlight indexes from scratch.
- Copying or downloading lots of files, such as restoring a backup or syncing a big folder.
- Folders that change constantly, like build outputs, caches or virtual machine files, which Spotlight keeps re-indexing.
How to fix high mds_stores CPU usage
- Confirm it in Activity Monitor. Press ⌘ Space, type Activity Monitor, open the CPU tab and sort by % CPU. Watch
mds_storesfor a minute: short spikes are normal, only steady high usage needs fixing. - Leave your Mac on power and awake for a while. First-time indexing can take an hour or more on a full drive, then it drops to near zero.
- Exclude busy folders you never search, such as build folders, caches and virtual machines. Open Spotlight's settings in System Settings and add them to the privacy list (named Spotlight Privacy or Search Privacy, depending on your macOS version).
- Exclude external drives you only use for backups the same way.
- Rebuild a stuck index if it never finishes: add your startup disk to that privacy list, wait a minute, then remove it. Spotlight starts a fresh index.
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