Help Trouble with files getting deleted from the sd card on shut down

[kalanaka]

I copy files from my tablet storage to my ext sd card storage. I shut off the tablet. When I turn it on, all the files I copied are gone. The folder I created is still there but its empty. Why.?

 

[Rukbat]

Because, for some reason, even though you think you're copying the files, you're not.

 

[kalanaka]

What am I doing wrong?