Only two Jam Packs appear in library
I've tried several times to install the Jam Pack instruments on my MacBook Pro - from the Logic Studio pack. It seems that the files for these instruments have been successfully saved to the computer, but for some reason only two folders appear in GarageBand and in Logic Pro - Garageband also displays the folders for the other Jam Packs, but shows them as being empty. As both GarageBand and Logic Pro are having this problem, I presume it must be a Jam Pack issue..
Any ideas?
MacBook Pro (late 2008), Mac OS X (10.6.2)