I have two 1tb my book essentials external harddrives and my pc only sees one at a time, i can hook up one and see it but if i hook both up it will not see the second one, can anyone help me with this.
Normally you can plug as many USB devices to the available USB Ports on your CPU (computer).
The CPU (computer) should recognize all of them.
Please make sure that you have install all of the windows updates, service packs, patches, drivers, etc.
Try contact your computer manufacture tech support for all of your computer software updates and drivers.
After that you can connect both WD external drives and both should work at the same time.
This thread is for a different brand of drive, but perhaps the solution will be the same: