@Zing Sorry if I don't explain better ^^U
It is correct Rpi3 installing the Recalbox 6.0 through Etscher on an SD card and using the external hard drive for bigger roms (N64, PSX) as it has more space.
For the SD card everything is correct, the thing is that for the hard drive when I put the Recalbox 6.0 with the Etscher sometimes the Rpi 3 does not recognize it. Also I was planning to copy the backup that I made with all the roms for the hard drive, but when I plug it to the computer it does not appear the Share file as it always appeared before I do not know why so I can't copy them like I used to do.
On my computer I can see the SD card with the recalbox manager and like a normal file connected to the computer with all of the files.
So, in summary I need to fix in the hard drive a way that the Recalbox 6.0 appears like before to go inside each of the files (bios, Roms---> SNES, etc) to copy the games that I have saved and I need to fix it so everytime I put on the Recalbox ANYEXTERNAL appears the files from the hard drive and not the ones on the SD card.