Getting 2 external drives to show up?

I purchased two of the 3TB WD Elements External Hard Drives and when I connect both to my computer only one will show up. Both of them work if only one is connected. I can also connect one of them and another USB thumb drive. I just can’t get both of them to show up together. I can also see both of them under the hardware tab of windows properties, so I know they both are showing up.

I am running Windows 8.1, 64-bit OS

Thanks for your help!

It’s a Windows problem check this out