When zooming in on the timeline too far the audio waveform may show up blank.
- First, close down Camtasia 9 so it is not running.
- Click Start and type regedit and hit enter. This will bring up the registry editor.
- Browse to this folder. HKEY_CURRENT_USER\SOFTWARE\TechSmith\Camtasia Studio\9.0\Camtasia Studio\9.0
- Once you click on that 9.0 folder in the right hand pane will be many different registry keys.
- Locate the key called "UseHardwareRenderingForWPF". Double click it to edit it.
- Change the value from 1 to 0 as shown in the screenshot below and click OK.
Now restart Camtasia and see how it works.