SD card printing

Hi im tryin to use SD ramps, iv enabled it in marlin. the software pronterface can pick up the sd card and read the file. when i click on the file it loads the file and starts printing. however when i press the disconnect or pull out the cable from the pc it stops printing. the led is on on the arduino when i plug out the usb and the D1 and D2 is installed on the ramps.

Does anyone know where im going wrong.
Im naming the files test.gco this is ok isnt it?
thanks

I'm not sure if there's any relation but I recall seeing a vaguely similar issue at some point while reading the forum and ended up at this link, which discusses a conflict issue with the Y-endstop and SD operation, which then outlines a solution, although for printrboard, not the ramps.

In any case, maybe (or not) it relates. if not, sorry for the thread spam. Good luck.

Marlin is very susceptible to electtrical noise. My only thought is that unplugging the USB is causing an electrical "pop" thats crashing marlin. This is just a thought though, may be a totally unrelated issue.

you have D1 and D2 the correct way round yeah ?