Computer does not recognize 2 different MyBook drives at the same time

Hi,

I have an existing MyBook 2tb drive that is formatted as my F drive. I just purchased a second MyBook 3tb drive. Only one is recognized when they are both plugged into the computer. I tried re-formatting the new 3tb drive to be K, but it changed my 2tb drive to K as well. Is there anything I can do to fix this? 

Did you check in disk Management to see that both drives have a drive letter and are online? What OS are you using? Windows 7 has a disk collision problem that shows up on identical disks. I don’t know if that is your problem. Here is the fix http://community.wdc.com/t5/My-Passport-for-PC/Copy-files-from-one-drive-to-another/m-p/277504/highlight/false#M7587 see post 11.

Joe