If you do see a red message saying something along the lines of “Error: This disk needs to be repaired” you can just choose to click the “Repair Disk” button to start that repair process, that will work for any internal or external drive – unless the drive in question is your boot disk, then you will find the “Repair Disk” button is inaccessible. Verifying partition map for “APPLE Media”Ĭhecking the EFI system partition’s file systemĬhecking all HFS data partition loader spacesĬhecking Core Storage Physical Volume partitions Disk Utility should resemble something like the following screen shot:įor the vast majority of users, what you see will look something like this, finalizing with a message of “The partition map appears to be OK”, indicating that no errors have been found: You will find the window populating with messages about the drives health, messages that indicate things are fine appear in black, messages that indicate something is wrong appears in red. Click on “Verify Disk” in the lower right corner and let it run.Select the Mac hard drive from the left side menu and click on the “First Aid” tab.

Launch Disk Utility, found within the /Applications/Utilities folder.

Imac boots to os x utilities