Explorer crashes when accessing external HDD

[Nik2014]

I was copying data to my external HDD and suddenly it stopped with error "can't read from source disk". And now when I try to access the HDD, windows explorer crashes. I use windows 8.
The source disk and files are fine and working perfectly.
Please help!

 

[Phillip Corcoran]

test the external drive with SeaTools: http://www.seagate.com/gb/en/support/downloads/item/seatools-win-master/