When you are using a Mac, at times you might run into problems with Wma files as this is a Windows format. These are designed for Windows Media Player specifically and on your Mac there can be some conflicts.

The first selection is to download a player that will play these types of files. There is a Windows Media Player for Mac that sort of works but something like Vlc is a much best alternative. Vlc will open just about everything development it easier to play assorted formats that might not be native to the Mac. The same goes for when you are using Linux.

Other times you have been playing Wma files successfully for months but consideration that one just doesn't want to open or answer at all. The issue is that you have a protected file that needs the Windows version of media player to confirm the Drm restrictions on the file. This must be addressed before the file can play again.

Really the only selection you have with such a file is to boot it up on a Windows facility and get it to open. If you have permission to convert the file, convert it from the protected Wma to something like Mp3. Take the converted file and use it on your Mac like any other media file. If you can't convert the file, you will have to deal with the Drm restriction on a Windows machine whenever it locks itself up again.

If you don't have permission to convert or copy it, then you shouldn't. You may have the proprietary to put it on your Mp3 player to use the media that way or you will have to repurchase the media in format that your Mac can handle. If you do this, look for files that are not protected by Drm as they are easier to manage.