Dorico Pro 4.1.1072 (May 30, 2022)
Dorico 4 Audio Engine 5.0.30.156
Windows 10 21H2 (Build 19044.1706)
I was playing with the new Dorico 4.1 (fab!) but shut it down completely when I went for a cup of tea. On returning, Dorico wouldn’t start up - on starting the Task Manager I found that both Dorico and the VST Audio Engine were both still running as background processes. By ending both Dorico would then start happily.
This didn’t happen with the previous version.
Edit: after another cup of tea and a reboot of the computer, all is now working as it should be. So - panic over, but maybe this post will be helpful to those suffering a similar problem.