Not all photos from SD card will upload to computer

[sjb0111]

I have a Nikon D700 and SanDisck Extreme 32 GB card. I shot a wedding and the photos it seemed were grouped into 2 different "sections" on the SD card. When I went to upload to computer not all the photos uploaded to. I can see all the photos on the camera but not on computer

 

[getochkn]

Is it possible the camera has a small amount of onboard storage and thats where the first group of photos are stored?