[Decode Mode] in the [Preferences] window may not be available for selection, depending on the device you are using.

On a Mac, you can select [Decode Mode] only if you are using a device that provides a proprietary feature.

If the device you are using does not support DoP (DSD over PCM), [DSD over PCM] is not available for selection.

If the device you are using does not support DSD Native, [DSD Native] is not available for selection.

If the device you are using supports DVD playback, you can still play DSD audio files when [Decode Mode] is not available for selection.