I have a music player that is able to save and restore AU parameters using the kAudioUnitProperty_ClassInfo property. For non apple AUs, this works fine. But for any of the Apple units, the class info can be set only the first time after the audio graph is built. Subsequent sets of the property do not stick even though the OSStatus code is 0 upon return. Previously this had worked fine. But sometime, not sure when, the Apple provided AUs changed their behavior and is now causing me problems. Can anyone help shed light on this ? Thanks in advance for the help. Jeff Frey