Dorico 4 and Audio engine - fails to start up

I am quite sure I have no HALion installed, as I only use Noteperformer (successfully with Dorico 3.5 still).
My Hard drive is chronically overfilled.

Your crashes have the Eucon component in them – I have heard about a potential problem with that. I’m waiting to hear back from someone about it

The latest one (14.51) is created with the instructions of opening the VST engine with the terminal. It appeared in the activity monitor, but disappeared after some time, as it happened before sometimes launching Dorico normally.

Can you try removing this component to see if it fixes the problem? It will be a bundle with ‘eucon’ in the name, probably in /Library/Application Support/Steinberg/Components. Just move it to a different folder and try starting Dorico again

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That’s ok with me. I updated Halion SE and now Dorico is started. It is solved with me. Thank you.

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Although it was stuck on „Launched Audio Engine“ for 3-4 seconds (which already made me doubt again).
If this regards the EuCon Protocol, I for now have no intention of using external consoles.

Dorico 3.5 however didn’t seem to really have an issue with this component ever.

But the new license system…

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That’s great to know. I assume you have an installation of Cubase which provides this component. Which Cubase version is it, and are you able to tell the version of the eucon component?

I had cubase installed a very long time ago. 6 years ago to be precise. I don’t remember which version it was, but I had both an LE AI Version as well as a Pro Version with a dongle from a project partner. I deleted it afterwards though.

The component is called „eucon65“ if that helps. If not I can happily share the exact component with you, if that would help.

Thanks - eucon65 may be all we need to know

I’m having similar issues. Can’t start Dorico 4 at all. 3.5 is still running fine. Can’t find a eucon65 file anywhere in my library, and my Halion Sonic SE is up to date.

Files attached! Good luck!


VST Engine Crashes Today Dorico (167.1 KB)
Activation (25.1 KB)
Dorico 4 (19.1 KB)
Dorico4 Force Quit Report.pdf (3.4 MB)

It definitely looks like the EUCON issue as well, based on your audio engine crash logs. Please make sure you’re checking the Library folder in the root of your hard disk, not the one in your user-level folder.

Thanks for the suggestion… but I apparently have no Components folder in my root-level library Steinberg folder (see attached).


It’s definitely there, but it is a hidden folder in the root of your harddrive.
Open Finder and from the menu choose Go > Go to folder
and in there type


and then enter. From there navigate further to the components folder.

I’m having the same trouble and I have no eucon component in the I’m pretty certain–correct library.

Also, I did reinstall D4

@lafin , are there any crash logs of the audio engine?

If you can’t find, please do following:
Open a Terminal window (/Applications/Utilities/ and then copy and paste the following command:


Then post the output from the Terminal window. Thanks

You were right! But… I took the component bundle out and am still having the problem.


Please go to /Users/your-username/Library/Logs/DiagnosticReports and look for any crash reports in there with names beginning with Dorico or VSTAudioEngine, zip them up, and post them here, so we can see what’s going on now.

@Chewy_Papadopoulos , then you must have new crash files. Please post. Many thanks.

Here you go, and thank you!


VSTAudioEngine5_2022-01-12-082326_The-Big-One.crash (69.6 KB)
New Dorico 4 Force Quit Report.pdf (3.4 MB)
VSTAudioEngine5_2022-01-12-081718_The-Big-One.crash (69.1 KB)
VSTAudioEngine5_2022-01-12-081552_The-Big-One.crash (69.1 KB)
VSTAudioEngine5_2022-01-12-081427_The-Big-One.crash (69.1 KB)

PS For what it’s worth, I just re-installed the Halion SE update as well. The problem endures!