Error message: "Disk inserted not readable by this computer"

When I start up my Mac OS 10.9.3 system I see on my screen appears a message:  “The disk you inserted was not readable by this computer.”  I am given the choice to either “ignore, or eject.”  I have used both, but the problem persists.  When I disconnect MY Book Studio at startup, this error message goes away.  I think it’s something to do with My Book Studio Drive that is connected using a Firewire400 Cable.  This drive is used  to perform timed backup.  I have reformatted the disk, but this hasn’t corrected the problem.   I have visited “WD SmartWare” to download upgrade to the SmartWare, but the software scans for a connected USB connection, but as I’ve said earlier, I am using Firewire400. I am confused about what to do to eliminate this annoying message at startup.  Any suggestions?

Hello,

Have you tried replacing the Firewire cable? Also make sure the drive is plugged in directly into a wall outlet.