Just some ideas/observations that might or might not relate: Can you read the card from your PC?
For what its worth the "preparing sd card" is a message I get when first turning on one of my android units and on another when I have taken the card out and put it back in. If I ignore it it goes away.
As to the damaged part????
Also on some sd cards when I put them in my pc card reader it reports they have problems and asks to scan them or something - I just close the window and proceed without letting it do anything and all is well with the card.