i had the same problem with WMDC in RTM.
So i downloaded a beta, and from then on i was able to work!

"MikeDaGeek" wrote:

> I too have a i730 and have the same issue ... are you guys able to perform
> the other sync actions?
>
> folders
> notes
> etc?
>
> I can explore my device and marry it to the media center to sync to innate
> memory but not the SD card ....
> THere is a Windows Mobile Device Center beta 3 that is supposed to help but
> I have downloaded it and tried with no change.
>
> "dbrlv" wrote:
>
> > Same problem her have you heard anything?
> >
> > "Tom Huseby" wrote:
> >
> > > Since installing Vista RTM I no longer see my 4GB SD card to sync with in
> > > Media Player 11. I can see the local storage on my pocket PC just fine. I
> > > have installed Windows Mobile Device Center Beta 3... It worked fine in Vista
> > > RC2.