Via an email from Western Digital:
As we previously announced, Western Digital received reports of Western Digital and other external HDD products experiencing data loss when updating to OS X Mavericks (10.9). Our investigation to date has found that for a small percentage of customers that have the WD Drive Manager, WD Raid Manager and/or WD SmartWare software applications installed on their Mac, there can be cases of a repartition and reformat of their Direct Attached Storage (DAS) devices without customer acknowledgement which can result in data loss. We have an updated version of the software that fixes this issue. We strongly recommend that you install this updated software. Please contact our service and support team with any questions.
Below are links to download the software:
WD Drive Manager for Mac Version 3.1.0.
WD SmartWare Version 1.3.6 for Mac 10.5-10.9.
This email arrived from Western Digital last night. We wanted to share it with our readers as soon as possible.
Dear WD Registered Customer,
As a valued WD customer we want to make you aware of new reports of Western Digital and other external HDD products experiencing data loss when updating to Apple’s OS X Mavericks (10.9). WD is urgently investigating these reports and the possible connection to the WD Drive Manager, WD Raid Manager and WD SmartWare software applications. Until the issue is understood and the cause identified, WD strongly urges our customers to uninstall these software applications before updating to OS X Mavericks (10.9), or delay upgrading. If you have already upgraded to Mavericks, WD recommends that you remove these applications and restart your computer.
The WD Drive Manager, WD Raid Manager, and WD SmartWare software applications are not new and have been available from WD for many years, however solely as a precaution WD has removed these applications from our website as we investigate this issue. .
The Western Digital bundled software has been an issue for quite some time, and it is one of several reasons MacMedics does not resell the Western Digital external hard drives. If you have this software, you should NOT use it, and frankly you don’t need it. Any external hard drive will work with Time Machine, and that is all you need for a safe back up.
If you have questions about this, please feel free to give us a call.