AudioMixerSnapshot.TransitionTo doesn't work if called from Monobehavior.Start

Unity Engine
1

While testing in the editor using Unity 5.0.0b12 on Mac.

I’m trying to implement an audio mute / toggle button to set a particular snapshot / state in Start() based on a playerPrefs. The default selected snapshot in the audio mixer is ‘volume on’. refreshMixer is called as expected by the ValueChanged event.

With hack == 0, if I run the app once and mute the audio, then re-run the app the audio will not be muted because the TransitionTo call fails (or is ignored).

If hack == 2, it works as expected.

I’ve submitted a bug report on this. I was wondering if anyone has encountered this issue and if they have a better work around?

using UnityEngine;
using System.Collections;
using UnityEngine.UI;
using UnityEngine.Audio;

public class musicManager : MonoBehaviour {

    public AudioMixerSnapshot musicOn;
    public AudioMixerSnapshot musicOff;
    public Toggle musicToggle;
    int hack;

    // Use this for initialization
    void Start () {
        int musicEnabled = PlayerPrefs.GetInt("MusicEnabled", 1);
        if (musicEnabled == 1) {
            musicToggle.isOn = true;
        } else {
            musicToggle.isOn = false;
        }
        hack = 2;
    }

    void Update() {
        if (hack > 0) {
            hack--;
            if (hack == 0) {
                refreshMixer();
            }
        }
    }

    public void toggleChanged() {
        int musicEnabled;

        if (musicToggle.isOn) {
            musicEnabled = 1;
        } else {
            musicEnabled = 0;
        }
        PlayerPrefs.SetInt("MusicEnabled", musicEnabled);
        PlayerPrefs.Save();
        refreshMixer();
    }

    void refreshMixer() {
        int musicEnabled = PlayerPrefs.GetInt("MusicEnabled", 1);
        if (musicEnabled == 1) {
            musicOn.TransitionTo(0.2f);
        } else {
            musicOff.TransitionTo(0.2f);
        }
    }
}
2

Additionally when targeting iOS, the Xcode build fails:

Undefined symbols for architecture armv7:
  "RegisterClass_AudioMixerController()", referenced from:
      RegisterAllClasses() in RegisterMonoModules.o
  "RegisterClass_AudioMixerGroupController()", referenced from:
      RegisterAllClasses() in RegisterMonoModules.o
  "RegisterClass_AudioMixerSnapshotController()", referenced from:
      RegisterAllClasses() in RegisterMonoModules.o
ld: symbol(s) not found for architecture armv7
3

same =

Undefined symbols for architecture armv7:
  "_OBJC_CLASS_$_ASIdentifierManager", referenced from:
      objc-class-ref in DeviceInfo(DeviceInfo.o)
  "RegisterClass_AudioMixerController()", referenced from:
      RegisterAllClasses() in RegisterMonoModules.o
  "UnityPause(bool)", referenced from:
      -[UnityAdsUnityWrapper unityAdsDidShow] in UnityAdsUnityWrapper.o
      -[UnityAdsUnityWrapper unityAdsDidHide] in UnityAdsUnityWrapper.o
  "RegisterClass_AudioMixerGroupController()", referenced from:
      RegisterAllClasses() in RegisterMonoModules.o
  "RegisterClass_AudioMixerSnapshotController()", referenced from:
      RegisterAllClasses() in RegisterMonoModules.o
ld: symbol(s) not found for architecture armv7
clang: error: linker command failed with exit code 1 (use -v to see invocation