sansa clip won't recognize microsdhc card

Sounds like either you don’t have the card fully inserted into the slot, or the card and/or card slot is defective. Do you have another card to try? If it doesn’t work either, and you’re positve the card is ‘locked in’ (you’ll hear 2 faint clicks when it’s in there correctly), then I’d suspect the player’s card slot is bad and you should get it replaced under the warranty.