Can't get two My Book 4TB to show up in Explorer

I am trying to replace two WD My Book 3TB external drives with two WD My Book 4TB drives #WDBACW0040HBK-NESN on a Win7 64bit machine. We use these are part of our backup software. Every January I swap out the old drives for two new ones. This is the first time I’ve had a problem with this procedure.

The problem is only one of the new drives will show up in Explorer at a time. I have tried every combination of cables and ports but only the first one plugged in shows up in Explorer and Disk Management.

Both WD drives show up under Computer Management and both show up as USB drives I can Safely Eject. I’ve updated the drivers on both, Ran the WD Quick Formatter on one, Formatted one through Disk Management.

I’ve checked this on two different Win7 64bit machines with no luck on both.

When I connect one of the older 3TB drives with the exact same cables, both the 3TB and a 4TB show up in explorer.

Am I missing something simple?


I think it’s a disk signature collision problem in Windows. This link explains how to fix


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