[Problem Solve][3DP][SD card] Print at the middle then stuck

Q: Everytime print my object will stuck at the same point.
I felt strange about this.

A:
I find maybe I have two critical issue must to solve.

Issue 1:

[SD Card]

When I use GUI to look my sd care everything is fine.
But when I use command line to check my sd card, I find nothing in my sd card.
I felt something wrong, so I format my sd card and try again.

This is main issue about stuck at the same point when I am printing the object.

Issue 2:

[Mega 2560 Board + Ramp 1.4][Maybe]

Because I want try how to create the function about auto leveling.
I connect to wrong pin, then whole set have bad smell. (whole set = Mega 2560 Board + Ramp 1.4)

I just changed my board (Mega 2560 Board), but I find old board about ramp1.4 have little proble.
The problem is step drive. Everytime print corner line, when machine must return to another way.
The machine will create the line not smoothly.
After I use whole new set (whole new set = Mega 2560 Board + Ramp 1.4), step driver create corner line become smoothly.
The machine will not shake so serious.