Media player stop working on Vista? Look here.

Yeah. It's damn annoying, too. All of a sudden I fire up the Zune client or Windows Media Player (WMP), select what I want, and then hit play.  And nothing happens. The first time this happened I was having a really bad day so I said enough with this and rebooted. Fixed it, but that's a crappy way to fix it.

After some research, I came across this KB article[1] (Programs that play audio stop working and duplicate entries appear in the Default Format audio format list in Windows Vista).  While the article didn't give me the steps to fix the issue, it got me pointed in the right direction (and I did not see duplicate entries as the article said I might).

What I did was:

1. Open the Sound applet (mmsys.cpl)
2. Open the properties for the default device; select the Advanced tab
3. My default was set to "16 bit, 48000 Hz (DVD Quality)". I hit the Test button; nothing. I selected the lowest item ("16 bit, 8000 Hz (Telephone Quality)") and hit Test. It played. I set it back to the DVD Quality and hit the Test button. It played, too.
4. Ok your way out of the properties dialog and the Sound applet.
5. 'Fixed' - until it happens again.

It doesn't happen often, so I'll live with this 'fix' that takes thirty seconds; there may be (is likely?) a better fix than this, outside of the hotfix. I expect this to be fixed in SP1.

[1] http://support.microsoft.com/kb/930883/en-us