Spotlight problems

When Spotlight will not stop indexing

Updated 2026-07-31 · 4 min read

Constant mds_stores activity and a fan that never stops usually means indexing is failing and restarting rather than finishing.

Confirm it

mdutil -s /

and watch mds / mds_stores in Activity Monitor. Sustained high CPU for more than a day after any upgrade is not normal.

Common causes

A corrupted index that fails partway. Indexing restarts, hits the same file, fails again. Rebuilding usually clears it:

sudo mdutil -E /

An external drive mounting and unmounting repeatedly. A failing cable or a drive that sleeps aggressively causes re-indexing on every remount. Check Console for repeated mount messages.

Cloud sync churn. Dropbox, Google Drive and OneDrive rewrite files constantly. Each change is a re-index. Excluding the sync folder from Spotlight is a legitimate fix if you do not search it.

A backup tool writing continuously. Same mechanism.

Time Machine local snapshots being created and thinned.

Breaking the loop

Exclude the churning folder in System Settings → Siri & Spotlight → Spotlight Privacy, then rebuild once. If the loop stops, you have identified it.

To stop indexing entirely while you diagnose:

sudo mdutil -i off /

Remember to turn it back on — search stops working while it is off.

The permanent version of this problem

If your work inherently generates thousands of file changes — a build system, a sync client, a VM — a content index is fighting your workflow. A filename index handles the same churn far more cheaply, because a changed file means updating one record rather than re-parsing the document.

Common questions

Is it safe to turn Spotlight indexing off?

Yes, but search stops working. Use it to diagnose, then re-enable with sudo mdutil -i on /.

Why does my Mac index whenever I plug in a drive?

A newly mounted volume is indexed if indexing is enabled for it. Repeated mounting causes repeated work.