I’ve had my VelociRaptor Duo for about 5 months and now it is starting to crash, with my back up files. The funny part about it is the WD Drive Utilities says everything is fine with the drive but if I run Mac Disk Utilities is says one of the mirrored drives has failed and as a set it is degraded. So right now the WD Drive Utilites is a useless tool for diagnosing a problem with the drive. Should have picked another back up source.
I recommend you contact support directly for this. If your drive is still under warranty they will help you get a replacement for it.