Comment 12 for bug 1098615

I hope that you also take into account that not everyone uses PulseAudio on Ubuntu. I'm using Open Sound System and therefore I removed PulseAudio and with it also indicator-sound.

$ unity-tweak-tool
schema com.canonical.indicator.sound not installed
Traceback (most recent call last):
  File "/usr/bin/unity-tweak-tool", line 72, in <module>
    UnityTweakTool.Application()
  File "/usr/lib/python3/dist-packages/UnityTweakTool/__init__.py", line 88, in __init__
    self.run(pageid)
  File "/usr/lib/python3/dist-packages/UnityTweakTool/__init__.py", line 97, in run
    self.connectpages()
  File "/usr/lib/python3/dist-packages/UnityTweakTool/__init__.py", line 110, in connectpages
    from UnityTweakTool.section.unity import Unity
  File "/usr/lib/python3/dist-packages/UnityTweakTool/section/unity.py", line 742, in <module>
    Unity.add_page(unitysettings)
  File "/usr/lib/python3/dist-packages/UnityTweakTool/section/skeletonpage.py", line 48, in add_page
    page.refresh()
  File "/usr/lib/python3/dist-packages/UnityTweakTool/elements/option.py", line 62, in refresh
    self.ho.refresh()
  File "/usr/lib/python3/dist-packages/UnityTweakTool/section/sphagetti/unity.py", line 93, in refresh
    interested_players = gsettings.sound.get_strv('interested-media-players')
AttributeError: 'NoneType' object has no attribute 'get_strv'