Disk Utility is Apple's go-to macOS app for finding and repairing common disk errors, but if it's your Mac's internal disk that's the problem, then your Mac might not even start up into macOS.

It’s a good idea to check on the health of your Mac’s internal storage on a regular basis. You can do this using Disk Utility, an app that comes with every Mac. To run the check, you need to boot the ...