My self designed PCB shows a strange behavior in reading the microSD memory card. 
It seams to me like the USB connection is OK, because i was able to load the Bootloader and the midibox_NG app normally. 
But now to configure my setup the memory seams to have a failure reading the microSD card. I have an idea that it cold be a problem with the Switch pins i didn't mention in my design (they are al to GND).  
The red pin connects to GND as soon a card is inserted. The two Blue pins close as soon the card is inserted without connecting to GND. 
  
Did anybody ever see something similar like picture one shows?