MediaMonkey should update tracks (sync again) for those tracks that have different tags. As it sounds that this is the first sync you might end up with duplicates as MediaMonkey can't relate the songs on the device with those on the PC.

You could start with an empty device (delete all songs) and than thru playlists specified by you sync those songs to the device. This is often the best way to start.

In MM when you go to Tools, Options, Portable Devices, Zen Vision, Configure you can choose which folders you want to synchronize with your ZVM as well as the playlists. I particularly dont synchronize folders but Playlists. Anyways, once you do that and you synchronize, MM will ask you if you want to delete the files that you have chosen in the configuration below and that are not present in the ZVM. The songs you updated in your library will be updated in the ZVM if they are already there or be copied if they weren't.

Hello,

I just downloaded MM and am learning how to use it. I'm starting to clean up all my MP3s and when I'm ready to synch my Zen Vision M, I'm worried MM will dump all the music onto my player that is in my library. I just want it to fill in the missing info for albums already on my player. I don't want everything in my computer's music folder to go onto my player. Will this even happen, and if so, how can I avoid it?

Thanks in advance to anyone who responds.