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.

I’ve put together an essential foundation document for Mac users who may sometimes try to help support friends and family. Still having problems? Restart the Mac holding down Command-R to enter Disk ...

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 ...