Windows 7: wma 10 and licens

After last update round, my Windows 7 is behaiving oddly. When I record sound via my USB gramophone, and save the sound as wma10, then my MP3 player can't play it back anymore, showing it is missing a valid licence from microsoft to play the song.
Playing in mediaplayer is working fine.
What license is it I'm missing? Records made for 2 weeks ago in the same format, same wma-version, plays fine on my MP3-player.
I have tried to use systemrestore to roll back, but that does not help.

Sounds like the update is causing an issue. You will need to uninstall it.

~Lordbob