Problem
Dorico 3.5 hangs on launch. In the start screen, the following message is being displayed indefinitely:
"Audio engine: Waiting for connection"
Background
This problem can occur if you have installed an incompatible HALion Sonic SE version, for example by trying out Dorico 4 on an unsupported macOS version.
Solution
If this is the case, "downdating" the existing HALion Sonic SE installation to HALion Sonic SE 3.4.40 will solve the issue.
- Restart your computer to make sure no Dorico process is still running.
- Download and run this HALion Sonic SE uninstaller.
- Download and reinstall HALion Sonic SE 3.4.40.
Now it should be possible to start Dorico 3.5 again.