I have my own music or tracks I've purchased on my hard drive and some songs play in Windows Media Player & others in Winamp, but when I try to drag the file to MMM it says the file format cannot be read.
(above text copied from magix_music-maker-17-premium_info_en)
Note: I also purchase audio loops or kits and use in Magix Music Maker please note, if the audio is in 24 bit first convert it in to 16 bit because Magix Music Maker only support 16 bit audio.
Friendly advice: You will not get good quality of listening in Windows Media Player. Real Player is much better.
Hope this answer will help you. If need more help send message.
nihon94 said "Friendly advice: You will not get good quality of listening in Windows Media Player. Real Player is much better."
That may be true, but Realplayer is also an extremely invasive and annoying program. It will highjack your computer and max out your resources without warning. Every time I've tried to use it, I've been forced to remove it shortly afterwards.