hi Andrew, thanks for your answer.

I can see all the instruments checking the box " show realtracks N/A:" ; N/A appears in front of every instrument string.

Opening the real tracks button in the main toolbar a window message tell me that "no realtracks are installed. When they are installed, there will be folders in the real tracks folder....".

In effect, i can regurarly see the realtracks folder in Application/BIAB/RealTracks/, but the program doesn't do the same.

I purchased the pro version 2010.5 for mac.

Thanks for your help