I have an Orange Miami and my phone no longer recognises my memory card?

Maybe the contacts in the phone are dirty or there is some foreing material in the slot.

If the card can't go all the way in, or offer to much resistance, use a can of compressed air to dislodge the obstruction.
Try inserting and removing the card a few times. The friction may be enough to clean the contacts.
Try with another card that you know is good.

You may need to reformat the card. This will erase any content. You may need to use a card reader connected to a computer for that.

Electro
August 2012