I just put this up on another of the posts. This applies for any and all extensions.
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block moving mp3? Add a new rule under application and device control tab. Under add application control rule set. add a new rule for file and filder attempts. Enter*.mp3 for apply to the following files and folders. Under the actions tab define the actions (block, prevent move etc...)and voila you are done. APply this to the group you desire to apply to
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