Reference 4 Systemwide attempts to present detailed error dialogs if the audio playback engine fails. However, this is not always possible - there are scenarios where Systemwide cannot determine the cause of the failure.
There can be different reasons for this. For example, a sudden format change on the audio output device can be unsupported and cause a playback engine failure if the engine is in the middle of initialization. Other cases could involve uncommon channel layouts, unsupported sample formats, or exclusive access settings from other processes. In such cases, the "Audio playback engine failed to start" error dialog will be presented.
This will help the troubleshooting process and narrow down the cause of failure. Common anomalies to look for might include sample rate/format mismatches, blank setting fields, and other obscure things in Mac's Audio MIDI Setup and Windows Sound Control Panel. If the cause can be pinned down and fixed, proceed to Systemwide audio settings and hit the "Restart audio playback engine" button.