Following a Windows 10 update to 21H1 (OS Build 19043.1645) Dorico plays sound for a couple of seconds then falls silent. When I go to Halion SE in the VST rack I see this:
When you run Steinberg Activation Manager, does it show that your Dorico 4 license is fully activated as normal?
That certainly looks OK! But when HALion Sonic SE is loaded inside Dorico, it shows the “No License” error?
This is very mysterious. After restarting Dorico, I selected a note and played from that point. The music played for a few seconds, and then went silent. I did Play Mode, then VST Rack. I folded out VST Instruments. I clicked the 
button next to 03 - HALion Sonic SE. The usual Halion Sonic SE3 screen appeared, and then I saw almost instantly a dark overlay with the message as shown in the screenshot. I did this several times to be sure of having an accurate description.
But, thinking it might have something to do with the choice of instruments, I opened another project with different instruments. It played with no problems. Then I went back to the project where I encountered the message, and then it played as expected. So the problem, whatever it was, is gone.
I suppose I should have tried that approach before reporting the problem, but it did not occur to me that it might be something about the project, especially as the project played with no problems on my laptop. That, and the text of the message, really suggested it was some sort of setup problem.
I would suggest you update to HSSE 3.5.10 - I think that red “License missing” message is from 3.5.0, and there have been some bugfixes relating to licensing between that and 3.5.10. HSSE 3.5.10 is available from the Dorico category within the Steinberg Download Assistant.
Thanks for the pointer about the update.
