How to Reindex Spotlight on Mac to Fix Search and CPU

In short: When Spotlight stops finding files or the mds process pins your CPU, a rebuilt index usually fixes it. Here is how to reindex Spotlight on Mac the safe way, and how long to wait before the index settles.

Spotlight is the search that powers the magnifying glass in your menu bar, the search box in Finder, and the results you see when you start typing in Launchpad. Behind it runs a background process called mds (metadata server), along with helpers named mdworker and mds_stores. When the index those processes maintain gets corrupted or falls out of date, two things tend to happen: search returns nothing (or the wrong things), and one of those md processes sits near the top of Activity Monitor eating CPU and draining your battery.

The fix is almost always the same: force macOS to throw away the old index and build a fresh one. On Sonoma and Sequoia (macOS 14 and 15) you can do this from System Settings or from the command line, and this guide covers both.

First, Confirm It Is Actually Spotlight

Open Activity Monitor (in Applications > Utilities), click the CPU tab, and sort by % CPU. If you see mds, mds_stores, or mdworker running hot, Spotlight is rebuilding or struggling. That is normal for a little while after a macOS update, a big file copy, or a Time Machine restore. Give it 20 to 30 minutes before assuming something is broken. If it is still churning an hour later, or search is plainly failing, it is time to reindex.

Reindex Spotlight on Mac From System Settings

The graphical route is the safest and needs no Terminal. It works by adding your whole drive to the Spotlight privacy list (which deletes its index) and then removing it (which forces a rebuild).

1. Open System Settings from the Apple menu.
2. Go to Siri & Spotlight, then scroll down and click Spotlight Privacy near the bottom.
3. Click the + button and add your startup disk (usually Macintosh HD), or drag it in from Finder. Confirm if prompted.
4. Wait a few seconds, then select that disk in the list and click the - button to remove it.
5. Close System Settings. macOS begins rebuilding the index immediately.

Nothing you do here deletes your files. You are only clearing the search index, which macOS regenerates from your existing data.

Reindex From Terminal With mdutil

If you prefer the command line, or the settings route did not take, mdutil is the built-in tool for the job. Open Terminal (Applications > Utilities) and run these one at a time. You will be asked for your password because they touch system-level indexing.

Check the current status first:

sudo mdutil -s /

To erase and rebuild the index for your main volume:

sudo mdutil -E /

The -E flag erases the existing index so it gets rebuilt from scratch. If indexing was somehow turned off, switch it back on with sudo mdutil -i on / first, then run the erase command. On an external drive, point the command at that volume instead, for example sudo mdutil -E /Volumes/YourDrive.

How Long the mds Rebuild Takes to Settle

A full reindex is not instant. On a modern Apple silicon Mac with an SSD, a typical drive settles in 15 to 45 minutes. A large drive with hundreds of gigabytes of documents, mail, and photos can take a few hours, and it will run hotter and use more CPU the whole time. This is expected. Keep the Mac awake and plugged in, let it finish, and you will notice search results start reappearing gradually as the index fills back in. Once mds_stores drops back to near-zero CPU in Activity Monitor, the rebuild has settled.

If High CPU Keeps Coming Back

If mds spikes every day even after a clean reindex, something keeps invalidating the index. Common culprits are a failing drive, a runaway app writing thousands of temporary files, or a corrupted cache. Check Disk Utility > First Aid for drive errors, and clear stale user-level caches under ~/Library/Caches. Only touch caches inside your own ~/Library; never delete anything inside /System, which macOS protects for good reason.

When you do clear caches, do it safely: preview what will be removed first, keep the cleanup to user-level junk, and send items to the Trash rather than permanently deleting them. That way, if clearing a cache causes an app to misbehave, you can pull the folder back out of the Trash and undo it in seconds. Reversible beats regret.

A quick word on privacy while you are here: a disk cleaner has no reason to phone home. It reads and tidies local files, and that is a fully offline job. If you want to confirm a tool behaves, run a firewall like Little Snitch and watch whether it makes outbound connections it should not.

If you would rather let a well-behaved app handle the cache-clearing safely, our top free pick is CoreSweep — free forever, with an optional one-time Pro at $49, zero telemetry, and every removal sent to the Trash so it stays reversible. A strong best-value runner-up is SkoonMac, which is free with a one-time $19 Pro. Either way, the Spotlight fix above is the same, and now you know how to reindex Spotlight on Mac whenever search or CPU acts up.

Frequently asked questions

Does reindexing Spotlight delete my files?

No. Reindexing only clears and rebuilds the search index, not your actual data. macOS regenerates the index from the files you already have, so nothing in your documents, mail, or photos is touched. You are simply forcing search to start fresh.

How long does it take to reindex Spotlight on a Mac?

On a modern Apple silicon Mac with an SSD, a typical drive settles in about 15 to 45 minutes. A large drive with hundreds of gigabytes can take a few hours and will run hotter and use more CPU the whole time. Keep the Mac awake and plugged in, and search results will reappear gradually as the index fills back in.

Why is mds or mds_stores using so much CPU on my Mac?

Those processes are the Spotlight metadata server rebuilding or updating your search index, which is normal for a while after a macOS update, a big file copy, or a Time Machine restore. Give it 20 to 30 minutes to settle before assuming anything is wrong. If a process is still churning an hour later or search is plainly failing, reindexing Spotlight usually fixes it.

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