Is this a card that has worked before and now doesn't? Do other card(s) work in the unit? If a card is attempted to be installed backward, it can damage the internal connections and make the card slot inoperative. Also, there are restrictions on the type, size, and speed of cards that can be used (identified) within the device. Here is a link to the manual; check page 20 of the technical notes and index (page 230 of the pdf).
Answers & Comments
Is this a card that has worked before and now doesn't? Do other card(s) work in the unit? If a card is attempted to be installed backward, it can damage the internal connections and make the card slot inoperative. Also, there are restrictions on the type, size, and speed of cards that can be used (identified) within the device. Here is a link to the manual; check page 20 of the technical notes and index (page 230 of the pdf).
http://cdn-10.nikon-cdn.com/pdf/manuals/coolpix/L820RM_EN.pdf