mds_stores won't stop — what Spotlight is actually doing to your CPU
You check Activity Monitor because your fans are loud or your battery is draining fast, and there it is: mds_stores using 80–150% CPU for hours. You've never launched it. You can't close it. And it won't stop.
Here's what's happening: mds_stores is Spotlight — the search system built into macOS. It indexes your files so you can find them instantly with Command+Space. Most of the time it runs silently. When it doesn't, there's a reason.
When high CPU from mds_stores is normal
Spotlight needs to index your entire disk at least once, and re-index whenever files change significantly. These situations trigger heavy, temporary indexing:
- After a macOS update — the system often rebuilds the index from scratch. This can take 1–4 hours depending on how many files you have.
- After connecting an external drive — Spotlight indexes external volumes by default.
- After restoring from backup — all files are "new" to the index.
- After a large file transfer — copying thousands of photos or documents triggers re-indexing of those files.
In all these cases, the fix is patience. Let it finish. It will drop back to near-zero CPU on its own.
When it's stuck — and how to tell
If mds_stores has been running at high CPU for more than 6–8 hours with no obvious trigger (no update, no big file change), the index is probably corrupted and Spotlight is stuck in a loop.
Step 1: Check indexing status
Open Terminal and run:
mdutil -s /
You should see "Indexing enabled" and "Status: Indexing." If it says "Indexing enabled" but doesn't show active status after hours, the index may be stuck.
Step 2: Rebuild the index
The cleanest fix is to force a rebuild. Open System Settings → Spotlight → Search Privacy (or Siri & Spotlight on some versions). Add your startup disk (Macintosh HD) to the privacy list — this tells Spotlight to stop indexing it. Wait 30 seconds, then remove it. Spotlight will start a fresh index from scratch.
Alternatively, in Terminal:
sudo mdutil -E /
This erases and rebuilds the index. It will take time (an hour or more), but after it finishes, mds_stores should settle down permanently.
Step 3: Exclude folders that don't need indexing
If you have large folders full of files Spotlight doesn't need to search — virtual machine images, code dependency folders like node_modules, media archives — add them to the Spotlight Privacy list. This reduces both indexing time and future CPU usage.
Don't disable Spotlight entirely. Some guides suggest turning off indexing with mdutil -i off /. This breaks more than search — Spotlight powers Finder's file search, Mail's search, and other system features. Exclude specific folders instead of nuking the whole system.
The mds_stores family
You might see several related processes in Activity Monitor:
| Process | What it does |
|---|---|
mds | The main Spotlight metadata server — coordinates indexing |
mds_stores | Reads and indexes file content — the heavy lifter |
mdworker | Worker processes that parse individual files (PDFs, docs, etc.) |
If mdworker is the one spiking, a specific file type might be causing problems — often a corrupted PDF or a very large document that the parser can't handle.
Not sure if Spotlight is stuck or just busy?
Gigatidy checks indexing status, tells you whether mds_stores will finish on its own or needs a rebuild, and walks you through the fix — no Terminal required.
Try Gigatidy →FAQ
What is mds_stores on Mac?
mds_stores is part of Spotlight, macOS's built-in search system. It reads and indexes the contents of your files so you can find them with Spotlight search (Command+Space). It's a normal system process, not malware.
How long does Spotlight indexing take?
It depends on how many files you have. A fresh index on a Mac with 500,000 files typically takes 1–4 hours. After a macOS update, expect 30 minutes to 2 hours. Once the initial index is built, Spotlight only indexes changed files, which takes seconds.
Can I stop mds_stores from running?
You can't stop it permanently without breaking Spotlight search, Finder search, and Mail search. You can reduce its impact by excluding large folders (like developer caches or media archives) from Spotlight indexing in System Settings → Spotlight → Search Privacy.