Limit what Spotlight indexes

Spotlight powers searching in macOS, whether done from the menu bar’s magnifying glass icon, with ç+[ spacebar], Finder’s search bar, or elsewhere. It doesn’t work so fast by magic: it’s constantly updating its indexes of everything on your Mac. This can cause excessive activity (see page 21) or trip it up, resulting in failed searches. In  > System Preferences > Spotlight > Privacy, you can exclude locations you never need to search. If Spotlight isn’t working, add your startup disk (or others) here, wait a minute, then remove it again to force reindexing.