Last time this was encountered, the steps below resolved the Audio Issue.
Reinstall RingCentral Application
1. Close RingCentral Application
-Open Task Manager
-Look for Softphone.exe with the description of RingCentral for Windows
-Click on End Task
***Once Softphone.exe disappears, you can be sure that RingCentral for windows is closed***
2. Go to Start > Control Panel > Change View by: to Category > Click Uninstall a program > Locate RingCentral application > Uninstall
3. Restart the computer after the prompt of successfully uninstalling.
4. Go to http://downloads.ringcentral.com/sp/RingCentralForWindows to download the application.
5. Go to the downloaded application > Right click > Properties > Look for compatibility tab >
> Tick Run this program in compatibility mode for > Select Windows 7 > Close properties > Then double click on the application
***For other OS/Issues not resolved by the published KB, please let us know so that we can assist you with your issue.***