Processes
mds_stores, mds and mdworker
Spotlight's indexing processes. They read your files so Spotlight search can find them.
What it is
mds (metadata server) coordinates Spotlight, mdworker processes read individual files, and mds_stores maintains the search index on disk. Together they let you find files, emails and messages instantly.
They are busiest after a macOS update, after migrating to a new Mac, after connecting a large drive, or when many files change at once (for example a big download or a code project being built).
Should you worry?
Usually not. Heavy indexing is temporary and stops on its own, often within an hour or two. If it never settles, something may be changing files constantly, or the index may be damaged.
What you can do
- Leave the Mac on, awake and plugged in for a while so indexing can finish.
- Exclude folders that don't need searching (build folders, virtual machines, node_modules) in System Settings › Spotlight › Search Privacy.
- If indexing never ends, rebuild the index: add your disk to Search Privacy, then remove it again.