iTunes can't read all of music

[ElDiabloConCaca]

iTunes will play MP3 and AAC (as well as uncompressed formats: AIFF, WAV, Apple Lossless, etc.).

QuickTime will play unprotected WMA files with the Flip4Mac plug-in. The discontinued AudialHub program can convert the rest of the formats to something iTunes can use (OGG, etc.).

Nothing on the Mac will play a protected WMA file.

[Spartan Samuel]

So basically, if I convert the files to mp3 or whatever, it might lose the protection and iTunes'll play it? I've tried it with Switch and it worked, but it lost all information (artist, album, genre, etc.). Is there anyway to convert without losing the attached information?

[ElDiabloConCaca]

Yes, conversion to MP3 will strip protection (although that's in violation of the DMCA in the USA -- just a standard disclaimer, not passing judgement or anything here).

I don't have any experience with "Switch" so I can't really say how to retain album/artist/etc. information. MP3 stores that information in the "ID3" tag of the MP3 (extra information embedded in the MP3), but I don't know how WMA stores it -- whether it's embedded in the file like with MP3, or whether there's an external database file that keeps track of that info.