Update 2/19/2016: This issue is now resolved.
This is a temporary issue stemming from a recent YouTube update. YouTube VEVO videos downloaded as MP4 will have no audio. However there is an easy workaround until a product update is made available.
Download the FLV version of the video, then convert it to MP4 if that is the format you'd like to save.
Here's how to set Replay Media Catcher to prompt you for a desired video format:
- In Replay Media Catcher, click Settings.
- Navigate to the Internet Downloads tab from the choices at the top.
- For Preferred Download Format, choose Prompt.