.XWM File

The xwm file extension is used for audio files that contains music for The Elder Scrolls V: Skyrim computer game, created by Bethesda and released in November 2011.

These files are located within Skyrim - Sounds.bsa archive. This archive can be extracted with various BSA tools (see bsa file extension for more details) and the audio files with .xwm extension can be played with VLC player (although with lousy quality).

Seems XWM format is actually xWMA format, which is a subset of common WMA format. There is a tool called xWMAEncode.exe in Microsoft's DirectX SDK, which is able to convert xWMA format (so XWM as well) to WAV, which can then be converted to plethora of other formats like MP3 or FLAC.

To convert XWM to WAV follow these few steps:

Download Microsoft's DirectX SDK and locate the xWMAEncode.exe program

Extract music files from Skyrim - Sounds.bsa with any working BSA Extractor

Copy xWMAEncode.exe to the folder where you extracted the music from previous step

Launch cmd.exe and locate your folder with the .xwm files

Once in the folder, type xwmaencode file.xwm file.wav, where file is the name of one of the extracted .wxm files. If you want to convert more files at once, its probably better to create a batch file for it.

And that's it. You should now have the files in WAV and can convert it to any other file format. 

How to open:

VLC player can play *.xwm files although with poor quality.

How to convert:

You can convert *.xwm files to WAV with xWMAEncode.exe program from DirectX SDK.