Does Sandisk make an sdxc card in 32GB? I can't find one. But the real problem is why is slot one failing to accept another (any other sd)card. I've no problem with either my D7000 or D600 so I'd kind of suspect your slot one. I'd not force any issues but if you live close to an approved Nikon service place I'd have them take a look. In the short term maybe just use the 32 GB card in slot two. Does the 16GB go all the way down in slot two? Good luck!