Thanks for the info @rorywalsh
After compiling this dev tip, I have made a summary of the last tests with guiMode (“queue”):
AU, VST, VST3, open, close, plugin and session, everything is memorized and without the need to play audio, Ok!
Now on Mac, the external folder is recognized correctly. Developer name no longer contains spaces.
Also now, you can save all the parameters without the need to be playing audio.
I don’t know if I forget something with Mac. Windows is next…