Unable to mount ExFat external HDD (' stderr: ERROR:._.com.apple.timemachine.donotpresent' has invalid checksum)

Hi All,

I have an external hard drive(Western Digital My Passport Ultra 1TB) which I keep all my movies, work stuff and etc. Initially I formatted the drive in ExFat format in Mac OS X platform so that I can use it in Windows and Mac. Also Ubuntu seems to have a fix to read ExFat file systems[1].

But recently when I connected this external hard drive to my Ubuntu machine, it gave me this error(something similar) saying that it cannot mount the disk: 

Error mounting /dev/sdb1 at /media/rbuse/My Passport: Command-linemount -t "exfat" -o "uhelper=udisks2,nodev,nosuid,uid=1000,gid=1000,io charset=utf8,namecase=0,e rrors=remount-ro,umask=0077" "/dev/sdb1" "/media/rbuse/My Passport"' exited with non-zero exit status 1: stdout:FUSE exfat 1.0.1

stderr: ERROR:._.com.apple.timemachine.donotpresent' has invalid checksum (0x6634 != 0x4044). '

I was stunned because all my work was in there, especially my VDIs. 

So I started my research and one solution was to plug it back in to my Mac OS X machine and use the "Disk Utility" tool to repair it(Use "Repair Disk" button) [2][3]. When I tried this, the following error came up.

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 was like "Huh?!?!?" . I continued my research and found that if I attempt several times to "Repair Disk", it will work at sometime[4]. I tried like 20+ times, it didn't work.

So I googled more and found a command that should fix the broken external hard drive [5][6][7].

sudo fsck_exfat -d <device>

To find the correct value for <device>(eg : disk1s2) use the following command[8] to list down the device IDs.

diskutil list

At the end of the fsck_exfat command, I got the following error[9]. 

fsck_exfat: Could not update main boot region: Bad file descriptor

Sigh!.

As the last attempt to fix, I used the "chkdsk" command of Windows OS[10]. And IT WORKED!!. I ran the following command. It took sometime to complete the task. So be patient.

chkdsk /f <Volume_ID>

Here the Volume_ID refers "C:" or "D:" of the corrupted hard disk. eg : 

chkdsk /f D:

Hope this article helped!,

Thanks,
Hemika

[1] - http://askubuntu.com/questions/451364/how-to-enable-exfat-in-ubuntu-14-04
[2] - https://bbs.archlinux.org/viewtopic.php?pid=1481063#p1481063
[3] - http://osxdaily.com/2014/01/27/verify-disk-command-line-mac-os-x/
[4] - http://beshoy.girgis.us/2013/11/solved-error-disk-utility-cant-repair-disk-backup-many-files-possible/
[5] - https://discussions.apple.com/message/24958301#24958301
[6] - http://craigsmith.id.au/2014/07/06/repairing-a-corrupted-mac-osx-exfat-partition/
[7] - https://developer.apple.com/library/mac/documentation/Darwin/Reference/ManPages/man8/fsck_exfat.8.html
[8] - https://discussions.apple.com/thread/4154638?start=30&tstart=0
[9] - https://discussions.apple.com/thread/4154638?start=45&tstart=0
[10] - https://www.microsoft.com/resources/documentation/windows/xp/all/proddocs/en-us/chkdsk.mspx?mfr=true