However, Spinrite costs $89, but you get a lifetime personal licence and a money back guarantee if it disappoints. If it was a transient error from a physical jolt or a voltage spike during a write and the disk is otherwise in good health, you can continue using it. It’s far more persistent than any OS or the drive’s internal error recovery logic. Spinrite can often recover unreadable sectors by doing its own error correction on the aggregate data accumulated from many reads. Unless you can boot your iMac into Linux and DOS utilities (I don’t know whether that’s possible) you’ll need to take out the hard disk and temporarily attach it to a PC. Take a look at Advanced Hard Disk Tools in the Restarters Wiki. File system repair utilities are of limited use in such cases. It sounds like you’re disk has got physical surface defects. Problem -69842 occurred while restoring the original mount state.Restoring the original state found as mounted.The volume Govind's could not be verified completely.Incorrect block count for file 2018.09.18.G80.asl.Performing fsck_hfs -fy -x /dev/rdisk0s4.Restoring the original state found as unmounted.

The volume Macintosh HD could not be verified completely.Performing fsck_hfs -fy -x /dev/rdisk0s2.Ran disk utility first aid to check internal HDD Once this is completed, click Done If you would like more info about the state of your before first aid was run, click Show Details.Please help to recover data… as I do not have a back up.(Note: If after doing this a second dialog box appears saying 'First Aid needs to temporarily lock the boot volume' Click Continue

When prompted if you would like to run First Aid, click run.

Select the Hard Drive you would like to check from the list of volumes.

Open Disk Utility, which is in the Utilities folder within your applications folder.

Repairing Disk Permissions with First Aid on OS X El Capitan and aboveįollow these steps in OS X El Capitan or above: You can use first aid to do this manually for external hard drives. Beginning with OS X El Capitan, system file permissions are automatically protected, It's no longer necessary to verify or repair permissions with Disk Utility on OS X El Capitan and above, as this is done routinely on the start up disk. In OS X Yosemite and earlier, Disk Utility can be used to Verify and Repair disk permissions. You can see a file or folder's permissions in the Sharing & Permissions section of its Get Info window.

If a file's permissions are no longer set correctly, software that uses the file (such as Serato DJ) might not work correctly. Permissions are file settings that affect the ability to read, write, or execute (open or run) the file.

First aid failed on external hard drive