Yes.. This happens to me sometimes. If I restarted Toribash it is still 0.. So I have to restart the computer to get back to 1 again.. But its only "Sometimes"
But I did.. I opened default.cfg in Toribash folder and set the volume to 0 and saved it.. Then I opened it again and set it back to 1 and The volume is fixed now..
Or
Right click Toribash click Properties
then in Target section.. i add -volume 1 I'm not sure if thats the code in it :X because this never happens to me now..