I've been able to pinpoint the issue further. It only occurs if you try to switch from a key-switched instrument to anything else. I was trying to switch from a KS with limited articulations (I originally thought that was all I would need) to a more comprehensive KS. But it also crashes when switching from KS to non-KS. I guess I will just have to plan ahead a little more, but it kind of takes the spontaneity out of the creative process.

Which of the VST plug-ins are you using: the multi-output one, or the single-output one, or the VST3 one?

How are you switching the instruments? Manually, or with some automatic method (I didn't think you could send instrument changes to ARIA outside of Finale.)

In this case I'm using the multi-output plugin. I'm not trying to switch the instruments throughout the course of the piece, but rather replace the instrument assigned to the track at the beginning. The original instrument didn't give me as many articulation choices as I ended up needing. As I said in my update post, it appears to be related to changing a KS instrument to anything else (KS or non-KS).

Can you change instrument in the standalone app, and in the plug-in in other apps?

I can make the change in the standalone app, and it appears to work fine. I don't have any other DAWs to try the plug-in in. 

Any further ideas? I really don't want to abandon this piece, as I think it has promise. Re-doing it is simply too much work.

Do you have any other plug-ins that might be interfering somehow? Maybe remove all other third-party plug-ins except ARIA. ARIA works for me in Logic, Finale and Dorico, and there aren't any 'known problems' of crashing.

Hi Ben. I tried making a test piece with only GPO5 in it. I set up a track of Section Violas Short Bows KS AG, and recorded a couple of measures. I changed the articulation and things worked fine, but the only articulations available are Auto Alternate, Bow 1 and Bow 2. I wanted pizzicato, so I changed the instrument to Violas KS, and nothing crashed, but when I attempted to change the articulation to pizzicato it just reverted to auto alternate. I tried other articulations, but everything always reverted to auto alternate. Don't know if that sheds any more light on the issue. Going forward, I think I will always choose the generic KS version of an instrument (if available) so that I can change to any of the available articulations. For the current piece, I just used another set of strings. Not what I wanted, but it's passable.

Thanks - George