Windows 10: all attempts to open capture devices returned IntPtr.Zero

[ghost]

OpenTK.Audio.AudioDeviceException was unhandled
  HResult=-2146233088
  Message=All attempts to open capture devices returned IntPtr.Zero. See debug log for verbose list.
  Source=OpenTK
  StackTrace:
       at OpenTK.Audio.AudioCapture..ctor(String deviceName, Int32 frequency, ALFormat sampleFormat, Int32 bufferSize)
       at KeybaordAudio.Program.Main(String[] args) in C:\Users\live\Downloads\KeyboardAudio-master\KeyboardAudio\Program.cs:line 43
       at System.AppDomain._nExecuteAssembly(RuntimeAssembly assembly, String[] args)
       at System.AppDomain.ExecuteAssembly(String assemblyFile, Evidence assemblySecurity, String[] args)
       at Microsoft.VisualStudio.HostingProcess.HostProc.RunUsersAssembly()
       at System.Threading.ThreadHelper.ThreadStart_Context(Object state)
       at System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
       at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
       at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
       at System.Threading.ThreadHelper.ThreadStart()
  InnerException: 

AudioCapture.DefaultDevice seems to be an empty string.

AudioCapture.AvailableDevices
Count = 1
    [0]: ""