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.

Repair Disk isn’t the first option you should choose if your Mac is ailing, but it is helpful when (for example): Performance has degraded Data is missing You are experiencing degraded system ...

OS X’s Disk Utility—which enables you to format, partition, repair, and perform other kinds of maintenance on disks (including SSDs, flash drives, and disk images)—is good for what it does. Yet for ...

There are a variety of maintenance routines that people can run in OS X, including the disk verification and permissions repair that come with the system, along with scripts such as cache cleaners ...