I have a external drive that is formatted as exFAT. It does not show up on my system when I plug it in. When I run Disk Utility, the drive appears on my system but I get the following message:

Updating boot support partitions for the volume as required.

Error: Disk Utility can’t repair this disk. Back up as many of your files as possible, reformat the disk, and restore your backed-up files.

I then ran fsck_exfat in a terminal and got the following:

sudo fsck_exfat /dev/disk2s1
fsck_exfat: Opened /dev/rdisk2s1 read-only
** Checking volume.
** Checking main boot region.
** Checking system files.
** Volume name is 2tb_WD.
** Checking upper case translation table.
** Checking file system hierarchy.
fsck_exfat: Couldn't read 131072 bytes at offset 302667137024: Input/output error

How can I recover the data on the external hard drive?

  • 1
    Use data recovery tools. What is the actual question? – STTR Jun 26 '13 at 17:28
  • Well Disk Warrior will not read the disk, what to you suggest? I was hoping fsk would repair the drive. – user233970 Jun 26 '13 at 22:05
  • r-tt.com MacOS ? see too data-recovery-software-review.toptenreviews.com/… – STTR Jun 26 '13 at 22:14
  • Remember to properly format your question. Use a right angle bracket > before each line of a blockquote, and indent code blocks with four spaces. – bwDraco Jun 27 '13 at 1:23
  • 1
    An input/output error most likely indicates bad sectors on the hard disk. – bwDraco Jun 27 '13 at 1:28

"fsck_exfat: Couldn't read 131072 bytes at offset 302667137024: Input/output error" ruh ruh raggy....

IO errors are usually VERY bad and could indicate a hardware failure - anything from bad clusters (which arn't too bad), bad cables (which are annoying) right down to gradual, complete, irrecoverable failure. , and at this point I'd urge you to backup whatever thats in that drive that means anything to you.I'd use ddrescue (probably available over something like macports or fink) and/or copy anything that means anything in whatever way possible and available to you (I've manually copied out files where even ddrescue failed), check disk health, then reformat the disk.


I have had lot's of problems with exFat and OS X (especially if the disk isn't securely disconnected). Disk Utility was never able to fix my drive. However a simple fix disk errors with Windows 7/8 would fix the problem immediately and make the drive work again with OS X.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.