Cannot Mount exFAT HDD on MacBook ( Yosemite )

I have WD Passport HDD of exFAT format , which was formatted on Windows Machine. I am not able to read it on my MBP 15' .

When I run Disk Utility,and ask it to Mount , it says cannot Mount HDD try running First Aid and please retry.

When I run First Aid/Repair Disk it says " The volume My Passport appears to be OK.File system check exit code is 0." Even after the first aid/repair disk it is not able to mount.

Additional Information:

Disk Identifier : disk3s1

Mount Point : Not mounted

File System : ExFAT

Connection Bus : USB