1. First, you can see the icon without background music in the opened PPT file.

2. You can click the "Select" button in the "Start" tab and click "Select Pane" in the open options.

3. You can open the "Selection Pane" window on the right side of the file, and you can see that "Background Music" is hidden.

4. Click the eye icon or "Show All" once to display the background music icon, and click Delete directly.