Maybe we can't prevent this?
You can prevent it, yes: By not blindly letting XMPlay associate with all file extensions claimed to be supported by all installed plugins. Most likely you are using in_adlib, which has MSC in its list of supported extensions. If you go to Settings -> Integration, you can remove MSC from the list of associated extensions. Generally it makes sense to only check the extensions there that you know you are going to use, because there will always be conflicts between extensions of obscure music formats and more common software. It shouldn't be up to XMPlay to decide whether a file extension claiming to be supported by a plugin is "worthy" being (manually!) associated with XMPlay or if there is a more important application on the system that already uses that application.
