My audio stopped working recently. There were no particular events that could have prompted this (maybe an automatic OS update).

I'm running Windows 8.1 on a Dell Inspiron.

Initial error message

At first I was getting the following error message on startup (and whenever starting a program that requires audio):

C:\Windows\system32\MMDevAPI.DLL is either not designed to run on Windows or it contains an error. Try installing the program again using the original installation media or contact your system administrator or the software vendor for support.

A system restore to a few days before the sound loss got rid of this error, but did not fix the issue of no sound. No sound icon appears in the taskbar.

Audio services not running

Upon checking services.msc, I see that Windows Audio is not running. Two of its dependencies, RPC amd Multimedia Class Scheduler are running with no problem. Windows Audio Endpoint Builder is not running. All services are set to startup automatically.

Attempting to start Windows Audio gives the error message:

Windows could not start the Windows Audio service on Local Computer.

Error 1068: The dependency service or group failed to start.

Attempting to start Windows Audio Endpoint Builder gives the error message:

Windows could not start the Windows Audio Endpoint Builder service on Local Computer.

Error 193: 0xc1

Attempted solutions

• Diagnosing the problem in BIOS: audio plays in this diagnostic, so must be a software problem
• System restart
• System restore
• Starting/restarting the services
  • Checking that Plug and Play and Power services are running (both of which have been reported to affect this)
• Fixing the problem in: Device Manager > Sound, video and game controllers (listed are Conexant SmartAudio HD and Intel(R) Display Audio)
  • Updating driver software
  • Disabling then re-enabling
  • Uninstalling, then restarting system to automatically install these
  • Updating driver software then manually choosing High Definition Audio Device
• Running the Windows audio troubleshooter, it gives One or more audio service isn't running and no options

Update: DISM RestoreHealth

I ran a

DISM /Online /Cleanup-Image /RestoreHealth

and got:

DISM failed. No operation was performed. For more information, review the log file.

The DISM log file can be found at C:\WINDOWS\Logs\DISM\dism.og

Checking the log file, the error(s) seem to start at around this point (previous lines omitted for brevity):

2018-05-11 15:30:54, Info                  DISM   DISM Package Manager: PID=6348 TID=2800 Processing the top level command token(cleanup-image). - CPackageManagerCLIHandler::Private_ValidateCmdLine
2018-05-11 15:30:54, Info                  DISM   DISM Package Manager: PID=6348 TID=2800 Attempting to route to appropriate command handler. - CPackageManagerCLIHandler::ExecuteCmdLine
2018-05-11 15:30:54, Info                  DISM   DISM Package Manager: PID=6348 TID=2800 Routing the command... - CPackageManagerCLIHandler::ExecuteCmdLine
2018-05-11 15:30:54, Info                  DISM   DISM Package Manager: PID=6348 TID=2800 CBS session options=0x48100! - CDISMPackageManager::Internal_Finalize
2018-05-11 16:28:57, Info                  DISM   DISM Package Manager: PID=6348 TID=6600  Error in operation: (null) (CBS HRESULT=0x80240021) - CCbsConUIHandler::Error
2018-05-11 16:28:57, Error                 DISM   DISM Package Manager: PID=6348 TID=2800 Failed finalizing changes. - CDISMPackageManager::Internal_Finalize(hr:0x80240021)
2018-05-11 16:28:57, Error                 DISM   DISM Package Manager: PID=6348 TID=2800 Failed processing package changes with session option CbsSessionOptionRepairStoreCorruption - CDISMPackageManager::RestoreHealth(hr:0x80240021)
2018-05-11 16:28:57, Error                 DISM   DISM Package Manager: PID=6348 TID=2800 Failed to restore the image health. - CPackageManagerCLIHandler::ProcessCmdLine_CleanupImage(hr:0x80240021)
2018-05-11 16:28:57, Error                 DISM   DISM Package Manager: PID=6348 TID=2800 Failed while processing command cleanup-image. - CPackageManagerCLIHandler::ExecuteCmdLine(hr:0x80240021)
2018-05-11 16:28:57, Info                  DISM   DISM Package Manager: PID=6348 TID=2800 Further logs for online package and feature related operations can be found at %WINDIR%\logs\CBS\cbs.log - CPackageManagerCLIHandler::ExecuteCmdLine
2018-05-11 16:28:57, Error                 DISM   DISM.EXE: DISM Package Manager processed the command line but failed. HRESULT=80240021
2018-05-11 16:28:57, Info                  DISM   DISM Provider Store: PID=6348 TID=2800 Found the OSServices.  Waiting to finalize it until all other providers are unloaded. - CDISMProviderStore::Final_OnDisconnect
2018-05-11 16:28:57, Info                  DISM   DISM Provider Store: PID=6348 TID=2800 Found the OSServices.  Waiting to finalize it until all other providers are unloaded. - CDISMProviderStore::Final_OnDisconnect
2018-05-11 16:28:57, Info                  DISM   DISM Provider Store: PID=6348 TID=2800 Found the PE Provider.  Waiting to finalize it until all other providers are unloaded. - CDISMProviderStore::Final_OnDisconnect
2018-05-11 16:28:57, Info                  DISM   DISM Provider Store: PID=6348 TID=2800 Finalizing the servicing provider(DISM Package Manager) - CDISMProviderStore::Internal_DisconnectProvider
2018-05-11 16:28:57, Info                  DISM   DISM Package Manager: PID=6348 TID=2800 Finalizing CBS core. - CDISMPackageManager::Finalize
2018-05-11 16:28:57, Info                  DISM   DISM Provider Store: PID=6348 TID=2800 Disconnecting Provider: DISM Package Manager - CDISMProviderStore::Internal_DisconnectProvider
2018-05-11 16:28:57, Info                  DISM   DISM Provider Store: PID=6348 TID=2800 Finalizing the servicing provider(MsiManager) - CDISMProviderStore::Internal_DisconnectProvider
2018-05-11 16:28:57, Info                  DISM   DISM Provider Store: PID=6348 TID=2800 Disconnecting Provider: MsiManager - CDISMProviderStore::Internal_DisconnectProvider
2018-05-11 16:28:57, Info                  DISM   DISM Provider Store: PID=6348 TID=2800 Finalizing the servicing provider(IntlManager) - CDISMProviderStore::Internal_DisconnectProvider
2018-05-11 16:28:57, Info                  DISM   DISM Provider Store: PID=6348 TID=2800 Disconnecting Provider: IntlManager - CDISMProviderStore::Internal_DisconnectProvider
2018-05-11 16:28:57, Info                  DISM   DISM Provider Store: PID=6348 TID=2800 Finalizing the servicing provider(IBSManager) - CDISMProviderStore::Internal_DisconnectProvider
2018-05-11 16:28:57, Info                  DISM   DISM Provider Store: PID=6348 TID=2800 Disconnecting Provider: IBSManager - CDISMProviderStore::Internal_DisconnectProvider
2018-05-11 16:28:57, Info                  DISM   DISM Provider Store: PID=6348 TID=2800 Finalizing the servicing provider(DriverManager) - CDISMProviderStore::Internal_DisconnectProvider
2018-05-11 16:28:57, Info                  DISM   DISM Provider Store: PID=6348 TID=2800 Disconnecting Provider: DriverManager - CDISMProviderStore::Internal_DisconnectProvider
2018-05-11 16:28:57, Info                  DISM   DISM Provider Store: PID=6348 TID=2800 Finalizing the servicing provider(DISM Unattend Manager) - CDISMProviderStore::Internal_DisconnectProvider
2018-05-11 16:28:57, Info                  DISM   DISM Provider Store: PID=6348 TID=2800 Disconnecting Provider: DISM Unattend Manager - CDISMProviderStore::Internal_DisconnectProvider
2018-05-11 16:28:57, Info                  DISM   DISM Provider Store: PID=6348 TID=2800 Finalizing the servicing provider(SmiManager) - CDISMProviderStore::Internal_DisconnectProvider
2018-05-11 16:28:57, Info                  DISM   DISM Provider Store: PID=6348 TID=2800 Disconnecting Provider: SmiManager - CDISMProviderStore::Internal_DisconnectProvider
2018-05-11 16:28:57, Info                  DISM   DISM Provider Store: PID=6348 TID=2800 Finalizing the servicing provider(AppxManager) - CDISMProviderStore::Internal_DisconnectProvider
2018-05-11 16:28:57, Info                  DISM   DISM Provider Store: PID=6348 TID=2800 Disconnecting Provider: AppxManager - CDISMProviderStore::Internal_DisconnectProvider
2018-05-11 16:28:57, Info                  DISM   DISM Provider Store: PID=6348 TID=2800 Finalizing the servicing provider(AssocManager) - CDISMProviderStore::Internal_DisconnectProvider
2018-05-11 16:28:57, Info                  DISM   DISM Provider Store: PID=6348 TID=2800 Disconnecting Provider: AssocManager - CDISMProviderStore::Internal_DisconnectProvider
2018-05-11 16:28:57, Info                  DISM   DISM Provider Store: PID=6348 TID=2800 Finalizing the servicing provider(GenericManager) - CDISMProviderStore::Internal_DisconnectProvider
2018-05-11 16:28:57, Info                  DISM   DISM Provider Store: PID=6348 TID=2800 Disconnecting Provider: GenericManager - CDISMProviderStore::Internal_DisconnectProvider
2018-05-11 16:28:57, Info                  DISM   DISM Provider Store: PID=6348 TID=2800 Finalizing the servicing provider(Edition Manager) - CDISMProviderStore::Internal_DisconnectProvider
2018-05-11 16:28:57, Info                  DISM   DISM Provider Store: PID=6348 TID=2800 Disconnecting Provider: Edition Manager - CDISMProviderStore::Internal_DisconnectProvider
2018-05-11 16:28:57, Info                  DISM   DISM Provider Store: PID=6348 TID=2800 Releasing the local reference to OSServices. - CDISMProviderStore::Internal_DisconnectProvider
2018-05-11 16:28:57, Info                  DISM   DISM Provider Store: PID=6348 TID=2800 Disconnecting Provider: OSServices - CDISMProviderStore::Internal_DisconnectProvider
2018-05-11 16:28:57, Info                  DISM   DISM Provider Store: PID=6348 TID=2800 Releasing the local reference to DISMLogger.  Stop logging. - CDISMProviderStore::Internal_DisconnectProvider
2018-05-11 16:28:58, Info                  DISM   DISM.EXE: Image session has been closed. Reboot required=no.
2018-05-11 16:28:58, Info                  DISM   DISM.EXE: 
2018-05-11 16:28:58, Info                  DISM   DISM.EXE: <----- Ending Dism.exe session ----->
2018-05-11 16:28:58, Info                  DISM   DISM.EXE: 
2018-05-11 16:28:58, Info                  DISM   DISM Provider Store: PID=1816 TID=6472 Found the OSServices.  Waiting to finalize it until all other providers are unloaded. - CDISMProviderStore::Final_OnDisconnect
2018-05-11 16:28:58, Info                  DISM   DISM Provider Store: PID=1816 TID=6472 Disconnecting Provider: FolderManager - CDISMProviderStore::Internal_DisconnectProvider
2018-05-11 16:28:58, Info                  DISM   DISM Provider Store: PID=1816 TID=6472 Releasing the local reference to DISMLogger.  Stop logging. - CDISMProviderStore::Internal_DisconnectProvider

Your Windows setup seems in a bad shape, when system utilities just fail.

I suggest two possible repair actions, where both will not lose you any apps or settings:

1. Run sfc /scannow to check the integrity of protected system files and replaces incorrect versions with correct ones.

2. Repair Install Windows 8.1, also called in-place upgrade install, to fix your currently installed Windows without losing anything.

First take careful backups, including a system image, before starting. I suggest using AOMEI Backupper Standard Free. Create also the AOMEI boot CD or USB and test that it can boot and can see both your system disk and the disk where the image backup is stored.

If these actions do not succeed, the next steps are destructive :

• Refresh Windows 8.1 repairs Windows by reinstalling it while keeping your files, Store apps and most of your settings, but all installed 3rd party desktop apps will be removed.

• Reset Windows 8.1 will give you a clean install, losing everything from your current Windows installation.