How to Limit Spotlight Indexing on Mac

How to limit Spotlight indexing on a Mac: turn off result categories in System Settings and add folders or drives to the Spotlight privacy list.

1. Open the Spotlight settings pane. Open System Settings from the Apple menu. Select Spotlight in the sidebar. On some Sequoia releases this pane is named Siri and Spotlight instead, with the same controls inside. The window lists every search category your Mac indexes.
2. Turn off categories you never search. In the Search Results list, deselect any category you do not want returned. Fonts, Developer, Presentations and Other are common ones to clear. Unchecking a category hides it from Spotlight results. It does not delete anything and it does not remove the file from disk.
3. Add folders to the privacy list. Click Spotlight Privacy near the bottom of the pane. In the sheet that opens, click the plus button and choose a folder or a whole volume. You can also drag items in from a Finder window. Click Done to apply the exclusion.
4. Test the exclusion with a search. Press Command and Space, then search for a file you know sits inside the excluded folder. It should not appear. Reindexing runs in the background, so give it a minute on a large volume before you decide the setting failed.
5. Disable indexing for a whole volume. For an entire disk, open Terminal and run sudo mdutil -i off followed by the volume path, such as /Volumes/Archive. Run sudo mdutil -s with the same path to confirm the state. Terminal may need Full Disk Access under Privacy and Security.