So I had a random problem this week with the Voice NameTag feature in the MFT Nav. I had setup a few favorite points and enabled the voice name tags feature so I could set them via voice control, everything worked great! A few days later I did a master reset (due to a an ipod issue) and my favorite places were cleared as you would expect, the voice tags however were not. When I tried to add the same favorite places back in and enable the voice name tags the system said entries with those names already existed. I activated sync and had it read out the available name tags, and sure enough it listed the favorites I had saved before the reset. Short of a hard reset I could not find a way to clear the old voice tags. what I did that finally worked was to re add the the same favorites I had before (same name and address) and NOT enable the voice tag. Then I waited for MFT to do one if its occasional self resets (usually every other day), when it did this the old name tags were re associated with the new favorites! So basically you have to wait for one glitch to solve a different glitch!
Simple right?
Hope this helps someone.