Sometimes, it would be followed up with these error messages: 'Disk Utility can't repair this disk' is one of the messages you will receive when First Aid failed.

Now, what should I do to fix this error without losing data on my drive? Back up as many of your files as possible, reformat the disk, and restore your backed-up files'. It gives me message 'Error: Disk Utility can't repair this disk. I am in the midst of trouble where Disk Utility is failing to repair the drive.