first try for me here

Than, here my problem : I've an old collection of roms with many of them obsolete. By using the frontend Qmc2,
I see easily the correct, medium and bad roms. So I decided to store them manually with folders

Then I discover Romcenter and tried to optimize my correct roms. By following the tuto, I succeed to obtain all roms green and Ok.
I precise that they were green and correct in Qmc2 but not in Romcenter who was show me roms green/yellow and red one.
But, here the problem. I used my correct roms from Qmc2 in Romcenter and now, despite the green icon of Romcenter I've a total
changement of them. Now I've 174 bad roms who don't work anymore !
Why this roms appear all green and good in Romcenter and wrong for a part of them in Qmc2.
I'm so disappointed, cause I've no solution now for restore them. Only DL another time...
Thank for your answer
https://www.dropbox.com/s/6bdwtlpfrlcdx ... 6.png?dl=0
https://www.dropbox.com/s/s5t0dclzojqqp ... 5.png?dl=0