Itunes volume frozen at zero and will not close

Question

hello, the volume slider in itunes intermittently gets frozen at zero. i can drag it to the right but as soon as i release the slider it snaps back to zero [all the way down]. when this happens itunes will not shut down, it closes and then reopens immeadiately, even if i chose to 'force close' it reopens. if i try to restart my mac itunes cancels the process. the only way to resolve, so far is to do a hard shutdown by hand. itunes will work for awile but eventually returns to this condition.
thanks for any ideas,
js

Answer 1

I copied this from https://discussions.apple.com/message/23501949#23501949.   It fixed my problem.
Couple of things ...
While the iPhone is actually syncing, you see something like this:
   (note the spinning "syncing" wheel)
You'll notice when it's done, it seems to be hanging and you get something like this - indefinitely:
  But, if you look again, you'll see the "eject" button has replaced the "syncing wheel":
So, at this point, just eject it and you're fine -- really.
And, if you don't trust that, then do this:
  Go to the Music tab of iTunes and add or remove just one song or one artist or one playlist.
  Then, click the Apply button in the lower right corner.
  You will notice that THIS way the Sync Process finishes cleanly.
Hope this helps!!