I am using the windows 7 on mine system and I have installed the 1 TB WD My Book drive on mine system and it was working perfectly and I have no issue with that. Now I am trying to install the second WD 1TB My Book drive and I have installed successfully. The problem occurred after installing a second 1TB WD My Book drive. I followed all the instructions, thereby throwing the unit into a USB hub. Windows found the drive, installed the drivers and informed the new album ready to use. Windows Explorer does not see the new drive. Devices and printers show two WD external hard drives. Disk Management also shows two units, but the second unit is not in line due to a "collision SignatureĒ. Now I donít how to solve this issue. can anyone suggest on this and so that I can solve mine issue.