Please be aware that there are serious data loss issues ongoing with Mac OSX Maverics and Western Digital drive sofware. Both the Apple support and WD forums have mutiple customer reports of total external drive data loss.
The data loss is not limited to systems activly using the WD software and drives, other vendor external hard drives are being lost.
Personally I just lost 1TB of Time machine backups on a Iomega external drive. I did have a WD myBook for a while about 2 years ago but was not aware the WD drive software was still active on this machine.
Current advice from Western Digital is to uninstall the WD drive software before going to Mavericks. Uninstaller is here .....