@#0 '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.'
https://hemika-kodikara.blogspot.hu/2015/05/unable-to-mount-exfat-extern...

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-di...
[5] - https://discussions.apple.com/message/24958301#24958301
[6] - http://craigsmith.id.au/2014/07/06/repairing-a-corrupted-mac-osx-exfat-p...
[7] - https://developer.apple.com/library/mac/documentation/Darwin/Reference/M...
[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/proddoc...