Windows media player is the most popular application that supports WMA files. It is a proprietary digital media player and media library application developed by Microsoft that is used for playing audio, video and viewing images on personal computers running the Microsoft Windows operating system, as well as on Pocket PC and Windows Mobile-based devices. Editions of Windows Media Player were also released for Mac OS, Mac OS X and Solaris but development of these has since been discontinued.
The abbreviation "WMA" means "Windows Media Audio" and is part of the Microsoft Windows Media technology. Since Windows Media Audio was developed by Microsoft, the format has grown to support all types of audio from high fidelity to multi-channel sound.
Compared with its versatility on Microsoft PC, WMA shows its shortage on Apple products including Mac computer, iPod, iPhone and iPad. Generally speaking, Apple doesn't allow people to import WMA, and the most common audio format on iPod and iPhone is MP3 or AAC. Therefore, if you want to enjoy the music files on your iPod, the best option is to convert WMA to M4A or MP3.
How to get this trouble fixed out? Audio Converter Plus comes up, which allows you to convert WMA files to M4A, MP3, etc.