When you render a project in Vegas Movie Studio or Vegas, you need to make sure that the format you select supports both audio and video. Follow these steps to select the correct format:

• Go to "File" > "Render As". If you are using Movie Studio, you can also go to "Make Movie" > "Burn to DVD".
• The window that appears contains a selection of formats and presets. When you select a format, read the preset description to make sure both audio and video are supported. For example, if you select MainConcept MPEG2 as your format and then select "DVD Architect NTSC video stream", you'll see that the descriptions says "Audio: None".
• If you want to make specific adjustments to the preset, go to the "Custom" tab. In most cases you'll want to stick with the original settings.