This usually happens if your PC's CPU usage is very high while you are recording.
This can often be caused by using GDI record mode (or allowing Automatic record mode to select it for you) to record moving video from sites like YouTube. Try using MPEG record mode instead:
- Click Settings
- Select Record Mode / Performance
- Enable 'I want to record moving video or games (MPEG mode)'.
Other things you can try:
- Reduce the size of area that you are recording
- Reduce the recording frame rate
- Close any unneeded apps that are running in the background.