[kite]

I think the best solution is, after installing Altiverb in OSX, launch AVerb whilst holding down the "Shift-lock" key ( it latches of course !), and Averb will ask you to locate your IR folder. Tell it where your folder is (ie the location of folder you used with OS9.x), and it should work just fine.

Re sharing IR's with other users -I don't think there is any problem with that -there are "home-made" IR's on the AudioEase website, for example, plus another site where you can download users' IR's-just don't try to sell 'em to anyone !!!!