Okay, thanks for trying. Then we need to take a performance recording during export on your machine. First please check if you have Windows Performance Recorder already installed. Therefore please that term in the Search field on your task bar next to the Windows icon. If you don’t, you need to download the Windows ADK from here.
Once installed, launch the Windows Performance Recorder, prepare Dorico for an export but don’t invoke, yet. Then click the Start button in the Recorder and immediately trigger an export in Dorico. After 10 seconds stop the Recorder and save the output to a file. Please zip up that output file and send to u dot stoermer at steinberg dot de.
In case of question or doubt please don’t hesitate to ask.
Thanks