You can’t ‘sync’ or otherwise use Windows Media Player to transfer songs to your memory card using a v1 model player. You have to manually drag & drop them from your computer to the card via Windows Explorer with your player in MSC mode.
That’s why so many people with v1 units have given up on MTP mode altogether and exclusively use MSC mode. It gets too confusing adding songs to the player in MTP and to the card in MSC and you can’t see the files you’ve added while connected in the other mode.
I’d suggest formatting your player, which will reset & erase everything and then re-loading all in MSC mode by drag & drop.
