How to Stop Windows Media Player From Automatically Downloading Codecs
Windows Media Player will download codecs as needed. If you use third-party codecs or want to save bandwidth, you can prevent Windows Media Player from automatically downloading codecs.
Because Windows Media Player does not include disabling codec downloads as an option, we can use Group Policy Editor or the Registry.
Video tutorial:
How to Stop Windows Media Player From Automatically Downloading Codecs - Registry
Because we need to create a new Key and DWORD, we created the registry files for you.