Most often this occurs when there is an issue with the sound card driver on the system. If the sound card driver is causing a crash or is not functioning correctly, the SWF file can become damaged and not play back properly.
To test for this condition, disable the sound card in Windows Device Manager and attempt another capture. If the recording plays back properly, the issue is with the sound card. Updating and/or reinstalling the most recent sound card driver is recommended as the first course of action.
If this does not resolve your issue, please contact Technical Support