macOS processes › Spotlight and search
What is mds_stores on Mac?
mds_stores manages Spotlight's index databases, the files on each disk that make searching fast. High CPU or memory from it means Spotlight is adding a lot to the index.
What it does
When mds and mdworker_shared extract information from your files, mds_stores writes it into the index and answers searches from it. Each indexed disk keeps its index in a hidden .Spotlight-V100 folder. Busy periods come in bursts and normally end on their own.
Why it gets busy
- Rebuilding the index after a macOS update or after you reset Spotlight.
- Large amounts of new data, like a migrated Mac, a restored backup or a full Downloads folder.
- An external drive being indexed for the first time.
- A damaged index that keeps being rebuilt.
Why is mds_stores using so much CPU?
mds_stores is busy when Spotlight is writing a lot to its index: after a macOS update, a migration or a big batch of new files. It settles on its own. If it doesn't within a couple of days, rebuild the index with sudo mdutil -E /.
Is it safe to quit?
macOS restarts it immediately. Quitting interrupts indexing, which then has to catch up.
Genuine Spotlight processes run from /System/Library/Frameworks/CoreServices.framework. An mds_stores anywhere else is suspicious.
How to calm it down
- Give it time with the Mac awake and plugged in. After a major update this can take hours.
- Exclude folders and external drives you don't need to search in System Settings › Spotlight › Search Privacy….
- If it's still busy after a couple of days, rebuild the index by running
sudo mdutil -E /in Terminal. It asks for your password, erases the index and re-indexes your startup disk, so expect more indexing for a while.
In SystemWatch
SystemWatch knows how much memory mds_stores normally uses and shows when it's well above that, and History shows whether a busy spell is winding down.
