Wait.
So. WD has software that, Worked for ALL previous versions of OSx with no glitches, errors or problems.
it works in windows, on all versions, with no glitches, errors or problems.
Yet, Upgrading to Mavericks now suddenly breaks it?
All things being equal here, it sounds more like Mavericks itself changed something on WD, which brought about the incompatibility.
Dont get me wrong, using 3rd party drivers from WD, or any that typically come with these types of drives is silly and full of bloatware, But you can't exactly blame WD for this particular sitation. But Kudo's on them for getting on the ball and recognising there is a problem and hopefully working towards fixing it.
As a software vendor myself. its quite painful when clients upgrade/update their platforms without checking with us, or verifying with us that our software is compatible. Yet they often will upgrade anyways without checking, then blaming us when our software, which has a pretty clear list of compaitibility options, doesn't work on a platform that is not listed as compatible.