When someone with a Mac tries to send me a Finale 2008 file (though it happened in previous Finale versions as well) using GPO, I get the following message and am unable to playback the file until I've re-loaded all the instruments:
"this document has been saved on Macintosh to request an Audio Unit plugin named: Native Instruments Kontakt Player 2 on Bank #1. On your current platform, this bank will not have a plugin loaded on it unless you choose one from the VST setup dialogue".
Is this a Finale problem? Or is it akin to NI's brilliant strategy to confuse people by naming a KP update with the exact same file name as a previous evrsion?
Why exactly are they "VST" on PCs and "AU" on Mac?
This is normal. Mac and PC's use the same sample information in different formats, VST & AU. You should follow the prompt and load the corresponding VST samples on your computer. If you send an edited version of this file back to a MAC user, they'll have to the same thing in reverse.
The Finale files themselves are still compatible between platforms. That hasn't changed. If you send a file with the softsynth instruments loaded, that transfers perfectly.
I think this is more of a MAC>PC issue, than a Finale issue. MACs use AU (audio units) as the type of sample, the PC with Finale will correctly recognize that AU units are what's being used for playback in the file, and it will tell you that it has to change to VST for PC playback.
Perhaps this is something that MM could encode into Finale to handle this all automatcially without displaying warnings.