In order to record system sound Movavi Screen recording products use a special virtual device that mirrors the system sound to speakers and, thus, the sound is possible to hear on a record. 

It is installed along with the Movavi application and is visible at your system sound settings. 

When the screen capture application on your machine is launched, Movavi Sound Grabber takes control over your sound device and the speakers icon on your task bar turns gray. 

There are certain cases when the sound might be lost:

1) When installing an application, access to the sound was not permitted. 

MacOS 10.13 brought in the new security feature that checks any loaded modules or any application core. 

Usually one sees the permission request at the first start of the program. 

The system may block Sound Grabber until one allows loading of the app. 

You might see the following in the Security&Privacy tab. 

GOLDEN SOFTWARE INC. is the developer of Movavi products.  

If the permission request did not come up or it is not possible to find the permission request in Security&Privacy, you can try re-installing Sound Grabber standalone. 

2) The installation error might have occured.

Please try re-installing the Sound Grabber application. 

Please close your copy of Movavi screen recording application prior to reinstalling the sound grabber.

How to remove the Sound Grabber utility

After that, please install it once again using this instruction

3) Some applications take control over the sound as well. 

If you use any third-party audio applications such as Sound Flower or similar, a conflict might occur. 

4) The sound device was changed during the recording. 

When one plugs in or ejects headphones during the recording process, it is possible to lose the sound because the source of the system sound changes. 

In the future releases the concept of a virtual device will be perfected in order to provide a higher variety of the use cases.