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How to fix exFat external drive issues?

neokao

macrumors newbie
Original poster
Aug 5, 2011
12
0
I have an external storage with 2 x 2TB ( Stardom 2Bay, JBOD mode ) that was working nicely with my Macmini .

Somehow since last week the disk is not readable anymore. I got the message that " The disk you inserted was not readable by this computer " and it asked to "Initialize", "Ignore" or "" Eject".

OS is the newest El Cpatian (10.11.5) and I've tried other enclosure and docking station and all saw the same message.

I also tried multiple computers (MBAs, MB, PC Win 7) and the same issue.


I then started trying to repair it on Terminal: "diskutil list" showed me the disk is now disk3 without partition.

So I did this first: sudo diskutil verifyVolume /dev/disk3 and I got the error message: " Error starting file system verification for disk3: Unrecognized file system (-69846)" .

Then I used "sudo fsck_exfat -d /dev/disk3".

Now I got the message:

"Opening /dev/rdisk3 ** Checking volume. ** Checking main boot region. fsck_exfat: Invalid jump or signature Main boot region is invalid. Trying alternate boot region. ** Checking alternate boot region. fsck_exfat: Invalid jump or signature Alternate boot region is invalid. ** The volume could not be verified completely."


So now how am I supposed to fix this? Thanks for your suggestions.
 

JohnDS

macrumors 65816
Oct 25, 2015
1,183
248
If you have a backup, the easiest course of action is to erase, reformat and repartition the drive. If not, you will probably need to try some data recovery software.
 

neokao

macrumors newbie
Original poster
Aug 5, 2011
12
0
I don't have all the files backed up. If there is an expensive way to fix this, I will try.
 

Fishrrman

macrumors Core
Feb 20, 2009
20,521
7,285
I second what JohnDS wrote above.

Your best way to "fix" this problem is to:
1. Backup
2. RE-INITIALIZE the drive(s) to Mac format (HFS+)
3. Restore your data.

If you have a Mac, store your important Mac files on a "Macintosh-formatted" drive.
Things will just work better that way...
 

neokao

macrumors newbie
Original poster
Aug 5, 2011
12
0
I second what JohnDS wrote above.

Your best way to "fix" this problem is to:
1. Backup
2. RE-INITIALIZE the drive(s) to Mac format (HFS+)
3. Restore your data.

If you have a Mac, store your important Mac files on a "Macintosh-formatted" drive.
Things will just work better that way...

I will certainly do that. However I need to backup some of these files from this drive first before re-initializing the drive.


I actually posted my question on that thread before I started this thread. No solution there.
 

JohnDS

macrumors 65816
Oct 25, 2015
1,183
248
There is a good chance that Data Rescue can still recover most if not all of your data. The link above will give a you a downloadable free demo which will list the recoverable files and allow you to recover one file as a test. If you want to recover the rest, you have to pay for a licence.
 

neokao

macrumors newbie
Original poster
Aug 5, 2011
12
0
Thanks for all the suggestions. I ended up rescuing all the files by using paid R-studio dat recovery software.
 

jreades

macrumors newbie
Aug 6, 2019
1
1
For the sake of anyone else who stumbles across this thread many years later: similar issue just encountered with a 4TB exFAT drive used for Photography attached to a Mac (but wanted to retain x-platform options). The drive was greyed out in Disk Utility and attempts to repair failed. Output from fsck were... worrying... which is how I ended up here after Googling "fsck_exfat: Invalid jump or signature Alternate boot region is invalid."

I downloaded Disk Drill and started trying to recover the partition. Disk Drill was quite happily working away and listing all my files, but I had also downloaded testdisk and wanted to give it a chance to have a look (I prefer free and command-line whenever possible). Test Disk reported that the drive was busy so I quit Disk Drill after saving the session and then suddenly realised that the drive had mounted successfully in the background!

My guess is that Disk Drill's free tool basically restored the partition map/boot region in order to make the drive recoverable and, in so doing, sorted me out without having to pay a penny and all of my data appears to be intact!

Trebles all round as Private Eye would say.
 
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thrwway1506

macrumors newbie
Oct 27, 2019
1
0
For the sake of anyone else who stumbles across this thread many years later: similar issue just encountered with a 4TB exFAT drive used for Photography attached to a Mac (but wanted to retain x-platform options). The drive was greyed out in Disk Utility and attempts to repair failed. Output from fsck were... worrying... which is how I ended up here after Googling "fsck_exfat: Invalid jump or signature Alternate boot region is invalid."

I downloaded Disk Drill and started trying to recover the partition. Disk Drill was quite happily working away and listing all my files, but I had also downloaded testdisk and wanted to give it a chance to have a look (I prefer free and command-line whenever possible). Test Disk reported that the drive was busy so I quit Disk Drill after saving the session and then suddenly realised that the drive had mounted successfully in the background!

My guess is that Disk Drill's free tool basically restored the partition map/boot region in order to make the drive recoverable and, in so doing, sorted me out without having to pay a penny and all of my data appears to be intact!

Trebles all round as Private Eye would say.

I signed up just to tell you that you are a lifesaver!! This worked.
 

Einston

macrumors newbie
Nov 20, 2019
1
0
Simply connect your exfat drive to a windows pc and check it for errors. chkdsk will check and reset the bits that need to be reset due to improperly unplugging the external drive from your mac.
 
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