Music App adds song info

I recently did a clean windows 8 installation, and added my own music to the music libary again.
When I launched the Xbox Music app/tile, it started adding all wrong album and songwriter information. It even started to change the track names :shock:.
I know that this used to be a function in windows media player, but it was always possible to turn it off.
Can't find that setting in the new music app tough.

Does anyone know how I can stop Xbox music from messing up my songs?

Swipe in from the right and hit Preferences, then disable the "Automatically retrieve Album art etc" option

Can you confirm for me, did this actually change the files themselves? For example did it move or rename the actual file on disk? And if you open the song in another player like er VLC maybe, does it display incorrect ID3 tags?