My ExFAT share partition is gone!!!

Hi, I followed your instructions and got this:

Opening /dev/rdisk0s3

fsck_exfat: Opened /dev/rdisk0s3 read-only

** 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.

Any ideas?

I have been getting that problem as well ever since I have formatted my shared partition of my internal drive to exFAT. Sometimes when turning on my MacBook or after a restart the partition would become corrupt! When I open Disk Utility it gives me a message that the disk cannot be repaired. I cannot access or recover any of my files on that partition. I routinely backup the files on the exfat-formatted partition as a safety measure.

Sometimes when I scan the partition with Disk Utility the partition would become corrupt! I get this message from Disk Utility.

Verifying volume “disk0s3”

Checking volume.

Checking main boot region.

Main boot region is invalid. Trying alternate boot region.

Checking alternate boot region.

Alternate boot region is invalid.

The volume could not be verified completely.

Error: This disk needs to be repaired. Click Repair Disk.

Verify and Repair volume “disk0s3”

Checking volume.

Checking main boot region.

Main boot region is invalid. Trying alternate boot region.

Checking alternate boot region.

Alternate boot region is invalid.

The volume could not be verified completely.

Volume repair complete.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 cannot go further than a week without the exfat-formatted partition becoming corrupt. It is very irritating. This is the only way to have a partition format that I can access with both Mac and Windows without relying on any third party drivers.

The problem seems to be in the Mac OS, and I'm distressed to hear that it is not fixed in Lion.

Apparently the Mac Hard drive partition information gets corrupted and forgets that the share drive is EXFAT.

I avoided the problem once when it occurred while in Disk Utility. Reasoning that the new partition information gets written on a clean exit I did a cold shut-down so the system would revert to a previoius setup. It did and the partition was OK. That can only be done before the new information is written, however.

It has happened three times now. The second time was while working in India and I was paniced because it happened after some critical work and before backup.

Good news is I discovered a simple recovery. It is time consuming but it works.

1. Boot in Windows, either native or via Fusion or Parallels

2. Clone the corrupted partition to an external drive using suitable software (I used Active@Disk Image)

3. Run CHKDSK /F on the external drive -- should instantly recover the file system

4. Reformat the share drive

5. Copy the data back from the external.

Obviously, fixing it in place would be an easy and instantaneous step if APPLE would fix Disk Utility's repair program to re-establish the link to the EXFAT partition. APPLE - PLEASE DO THIS

Also it seems that whatever bug causes the problem should be chased down with some urgency. Losing a whole partition is hardly good for Apple's reputation of quality assurance!!!

Best of luck

Just an addendum. It depends on how corrupted the system got. In this last case I did the procedure above to be safe, and also backed up the other partitions to be safe, and then tried chkdsk /f on the lost partition. Last time that didn't work, but this time it did. So, once everything is backed up, you can also try that. You have to run the command prompt as administrator to do this - right click on command prompt in the Accessories menu and select "run as administrator" Then in the command window type CHKDSK <drive> /f You can run it without the /f parameter to see what it reports before telling it to actually attempt to fix the problem.

Cheers

I have the exact same problem, after installing the new mac software update. mac thinks the exfat is a hfs drive and wants to format it.

How do you make drives appear in parallels? Since it doesn't mount it would be hard to share the drive.

thanks,

Rob

oh wow, I was about to unmount the drive so i could remove it from my mac pro in disk utility. Now I had the sudden option to repair the drive, I did and it worked! that's the way it should be!

Apart from it breaking down in the first place of course.

Hi, are you saying that MacOS now has an option for repairing the ExFat partition? That would be great. Before this, the only way I could do that was to repair it from Windows.

Looks like it, it didn not show up the first time, but after a few reboots I had the option to repair the exfat drive

I had the same problem after deleting some files from my exFat-partition (with OS 10.6.8 today and with an earlier version some months ago). SaiJohn's CHKDSK-method worked perfect. Thank you! You have saved me a lot of time.

As I could observe, Leopard always has problems with deleting (unlinking) files from exFat formated drives. I would be really happy if Apple would offer a working driver.

SaiJohn,

Same issue as all others here. Many thanks for the tip above, that fixed it! I will now just use linux or windows to delete files from the partition in future.

I have a related issue. I have a Samsung smart TV that can use an external HDD plugged into a USB socket to record TV programmes. This has some advantages over using our DVD recorder (e.g. it has access to HD Freeview channels which the DVD recorder doesn't) but I found when I wanted to put a recording on to a DVD that while the set can output TV programmes at the time of broadcast it has no facility to output recordings (except for the audio, as it has an output socket for playing the sound through a hi-fi).

The TV set didn't like the original format of the HDD and did its own formatting and testing process before the first recording. I tried connecting the HDD to my Mac to see if I could access recordings that way, but the system said it could not read the disc and offered to format it, which I declned. System Profiler and Disk Uility both report it is exFAT and verifying the disk with DU produces the boot sector error message others have reported.

So I'm now wondering two things: ℹ if I am able to repair the HDD with DU will the TV set no longer be able to read it, (ii) if that doesn't work, and I format it with DU, will the TV set be able to use it without reformatting? If so then I should be able to access the recorded files on my Mac and e.g. burn them to a DVD. I'm not that fussed about keeping the recordings (though they are those rather nice programmes on the history of music by that Goodman(?) chap), but it would be nice if someone happens to know the answer before I undertake any potentially destructive action.

PS: I should add that this is not a network issue -- the HDD is connected directly with a USB cable.

I use OSX 10.8.3 / Win 8 64-bit both EFI/GPT.

Same problem for me with a shared internal 2TB HDD formated in exFAT through Windows.

My files are finally back ! A huge thank to SaiJohn for his tip which instantaneously worked for me. No more exFAT for me on OS X that doesn't support this file system.

Bug not yet fixed in 2013, shame on you Apple >:(

I have OS X Yosemite 10.10.4 and have had this problem a number of times.

What you need to do is:

1. Open Terminal.

2. Run the following command:

sudo fsck_exfat -d disk0s4

, where disk0s4 is your disk.

3. Enter the root's password, when you're prompted to.

This might take a little while, depending on how many files you have on the disk.

4. Enter Yes, when this message appears: Main boot region needs to be updated.

5. Restart your computer, and everything should be fine.

Thanks, Lukasz. This is definitively the fastest and most easy solution. Worked for me like a charm!