'Missing VST?' I thought, but realised it is all basic building blocks
I drilled down to see where the problem objects are and they are not what I expected - see attachment.
Loaded up in standalone Bidule and no red.
I've attached the bidule as well - it's some kind of weak wave-reshaper/stereoizer designed as a post-stage for a similarly functioning synth layer.
To summarise: loading the attached file into PlogueVST shows red boxes, as standalone works fine.
cheers
