Hello!
I have a problem with 2.6.1: m4a sound files are not being imported in Windows! While my Unity 1.5.1 for iPhone does import them without problems, the Windows version simply ignores them.
They are there, in the project tree, but clicking on them opens nothing in the inspector. It simply says nameoffile (Default Asset). Nothing is heard in-game. Reimporting everything changes nothing 
It did work in 2.5…
No idea, anyone? Is this only happening to me? May I have installed something (who knows, VLC?) that is interfering with Unity when reading m4a files?
I can’t update my old projects if I can’t read m4a files
m4a files are only supported on the iphone as it is an iphone hardware capability.
Unity on the desktop uses ogg and normally the platform native compressed format (on mac its likely m4a as qt is the native, on windows you use the wma / wmv for audio and video)
Unity has its own audio importers and indeed m4a does not work on Unity 2.6 (Mac or PC), while it did work on Unity 2.5. I’d say it’s a regression.
–Eric
Really?
Nice, thought it just uses the native platform layers, which means the WMP dom on windows and whatever apple offers through the cocoa end on osx.
The docs:
It used to use Quicktime but that was a while ago.
–Eric
Wow, .mp3 is supported, but not .m4a? Glad I don’t use Unity anymore! 
Actually, the .m4a support on Unity iPhone is incomplete anyway. Almost all of the .m4a’s I have are Apple Lossless, not AAC. Those don’t import. Did they work in Unity 2.5?
I just use Blender to convert the .m4a format to a format that is acceptable for Unity.