"Where did you check? Your instrument library? And which files exactly did you play? The sampler files or or loops?"
I checked :
Library/Application Support/GarageBand/Instrument Library/Sampler/Sampler Files
Library/Application Support/GarageBand/Instrument Library/Sampler/Sampler Instruments
Library/Application Support/GarageBand/Instrument Library/Track Settings/Software/Drum Kits
in the first, I have the actual .aif sounds and they're all there, for the six drum kits.
I see that the Rock and Jazz Kits are much more sounds than the others. it seems a little strange.
the Rock Kit has about 200 sounds where the Dance Kit has only 25 :/
and on the HipHop Kit, I have some .aif but only 12 and 5 files with no extension (and I can't play them). and that is it.
in the second I have the .exs files for the six drum kits.
in the third, I have the .cst files for the six drum kits again.
I dragged and dropped an .aif file -taken from the Rock kit found in the Sampler Files, a kick or a snare, it works with all of them anyway- on my Garageband window and it showed like any other sound.
"Are the permissions o.k. on your Instrument Library?"
hmm, I'm sorry but I don't know what that is :/
"Do you get any warnings, when try to you use a Hip Hop Beat loop?"
no, it works fine and the computer doesn't give me any warning.
I tried to use different beat loops (Hip Hop and Rock), I tried to modify them just like in a software instrument, I added notes, I erased other notes...
and it worked fine and the sounds are what they should be.
the only problem is when I'm trying to choose a Software Instrument. there, the six drum kits are the same.