Click the partition on which your operating system is installed -- in this case it's called Mac OS X -- and, under the First Aid tab, click Repair Disk Permissions.

Mac OS X Snow Leopard offers a First Aid pane. This feature of Disk Utility lets you check almost any disk for errors, as well as repair any errors that it finds. Here are the two exceptions when the buttons are disabled: The start-up disk: Disk Utility can’t repair the start-up disk, which makes sense […] Disk Utility Can't Repair This Disk on Mac? Solve It Now! Jun 11, 2020 Top 10 Mac Disk Repair Software (macOS Catalina 10.15 Update) Disk Drill for Mac. Selecting the best disk repair software for Mac would be much more difficult if it … How to use Disk Utility on a Mac - Macworld UK

Making Bootable USB of Mac OS X with Disk Utility - YouTube

OS X Mavericks: How and why to Repair Disk | Computerworld

Mar 24, 2020

How to Make a Mac OS X Recovery Disk | TechRadar Get the Assistant If the Recovery Disk Assistant isn’t already in your Applications/Utilities folder, … 3 ways to fix 'Couldn’t Unmount Disk Error on Mac Fixing with Stellar Partition Manager Software. If the OS X is denying you to format, erase and repair … Verify and Repair a Mac Disk via Command Line in Terminal Jun 22, 2019 Mac os x can't repair the disk | MacRumors Forums