Replacing Hard drive B after failure


I have just replaced a WD Green drive with the code WD20EARX 2.0TB with a WD Green Drive WD20EZRX 2.0TB and I get a warning that that drive has failed and it is too small. Does the Drive have to have exactly the same code number to work or is something else amiss. Any help on this gratefully received.

Many thanks in advance.

Hello, In the WD My Book Live duo they have to be the same model that came with the drive, if they are not you might encounter the issue that you are having.