Dorico 3.5 Cannot be opened because of VST3 audio engine crashed(Attached to audio engine)

Hi there,
I’ve been used Dorico for a while, but after I updated my mac to Catalina(10.5.3), I just can’t open my dorico at all. I opened up my activity monitor, I just realized my VST3 audio engine is crashed every time I opened up my dorico. I don’t know how to fix it. Can anyone help me with it please?

Is the audio engine crashing or just not responding? These are technically two completely different things.
If it is really crashing, then please look under /Users//Library/Logs (I think that is the path) for crash log files of the VSTAudioEngine. Zip them up and send me please.
If the engine is just hanging and not responding, then please start the Activity Monitor, highlight the audio engine project, then, at the top of the window is a cog wheel icon, click on it and choose Sample Process and follow the on-screen instructions. Please post the corresponding file (after zipping it up). Thanks

The vst engine is not responding not crash (sorry for that). I followed your instruction and this is the file. Please help me to fix it.
Many thanks
Sample of VST Audio (132 KB)

Looks like a plug-in or component is screwing things up, therefore you need to temporarily disable all of them.
Please navigate to /Library/Audio/Plug-ins and rename the folders with VST in the name (e.g. add a underscore). By that Dorico won’t see those folders anymore during startup. After that renaming, start Dorico and see how it behaves then. Still the same?

Yes sir, Dorico can start now, but there is something come up.
Screen Shot 2020-06-20 at 3.08.49 PM.png

And sir could you tell me which plug in is screwing things up so i can delete or reinstall them.

I can’t tell you, but we have to find out. It’s a bit tedious but doable.
So you’ve renamed those folders. Now you do step by step:

  1. Stop Dorico
  2. Rename 1 folder to it’s original name
  3. Start Dorico and see if it still starts up
  4. If it starts up, fine, start with 1) again.
    If it hangs, then one of the plug-ins in the last renamed folder must be the culprit, continue with 5)
  5. Make a copy of the last renamed folder, then empty out that folder (not the copied one)
  6. Stop Dorico
  7. Copy one of the plug-ins (from the copied folder) into the empty folder
  8. Start Dorico
  9. If it starts up, fine, go to 6) again.
    If it hangs, bingo, you have found the culprit, it’s the plug-in you copied over last.

As I say, it’s a bit tedious. If you have lots of plug-ins, you might want to use a slightly different strategy, by copying plug-ins over in bulks of 5 or 10 or whatever you like. But the principle is always the same, once it starts hanging, you know it must be one plug of that group, and with the same sort of iteration you rule out the plugs within that group. So it should not become too difficult to find out.

Only one thing, at the very end make sure that every folder got renamed back to its original name. Then also the error message from your screenshot will go away.

Also, please let me know, which plug-in you then found to be the trouble maker. Thanks

Thanks for the method.
I Found that thing! It’s a folder in VST named 'VST". Thanks for your help again.
Screen Shot 2020-06-20 at 11.45.53 PM.png

But you just found a folder. What is all in that folder? Just one plug-in? If it is more than one, you have to continue with my mentioned steps 5 - 9.