macOS processes › Spotlight and search
What is mdworker_shared on Mac?
mdworker_shared processes do Spotlight's file reading. Several run at once, each extracting text and details from files so they can be searched.
What it does
mds hands batches of files to mdworker_shared, which runs the right Spotlight importer for each file type and returns what it found. A dozen or more copies during indexing is normal. They exit when there's nothing left to do.
Why it gets busy
- Big batches of new or changed files, such as after a migration or a large download.
- Formats that take work to read, like long PDFs, large spreadsheets or email archives.
- Disk images or external drives mounted for the first time.
Why is mdworker_shared using so much CPU?
Many busy mdworker_shared processes mean Spotlight is reading lots of new files. That's normal after updates, migrations or big downloads, and it ends when the batch is done.
Is it safe to quit?
Spotlight starts new workers as needed, so quitting one just delays its batch.
How to calm it down
- Wait. Many copies usually means a large batch that will finish.
- Keep big archives you never search, like raw video or build output, in a folder excluded in System Settings › Spotlight › Search Privacy….
- If they never stop, a fresh Spotlight index usually fixes it. See the mds_stores page for how to rebuild it.
In SystemWatch
SystemWatch combines every mdworker_shared copy into one Spotlight indexing row, so you see their total load instead of a long list, and History shows when the batch started and ended.
