I've got the transcend 16 gig too. Originally got it for my Panasonic TZ and it worked ok. When I bought my D7100 I tried it and I couldn't get it to work despite Transcend's website saying its compatible. Searched the Transcend site FAQ's and it says to set the meter standby time to as long as possible, tried that still nothing! By coincidence looking through the Nikon's manual earlier today I noticed a section on Eye-Fi cards, it says that the "Eye-Fi Upload" option is only displayed when an Eye-Fi card is inserted in the camera. Well the D7100 doesn't seem to recognise the Transcend card! very frustrating.