Windows 10 Update Failure (2021-05 Version 20H2) KB5003173

I am updating my Windows 10 PC to v20H2 and it's stuck at 20%, stating it cannot be installed due to error 0x800f0831:

• CBS Log:

  Info    CBS   Store corruption, manifest missing for package: Windows-Defender-ApplicationGuard-Inbox-Package~31bf3856ad364e35~amd64~~10.0.19041.789
  Error   CBS   Failed to resolve package 'Windows-Defender-ApplicationGuard-Inbox-Package~31bf3856ad364e35~amd64~~10.0.19041.789' [HRESULT = 0x800f0831 - CBS_E_STORE_CORRUPTION]
  Info    CBS   Mark store corruption flag because of package: Windows-Defender-ApplicationGuard-Inbox-Package~31bf3856ad364e35~amd64~~10.0.19041.789. [HRESULT = 0x800f0831 - CBS_E_STORE_CORRUPTION]
  Info    CBS   Failed to resolve package: Windows-Defender-ApplicationGuard-Inbox-Package~31bf3856ad364e35~amd64~~10.0.19041.789 [HRESULT = 0x800f0831 - CBS_E_STORE_CORRUPTION]
  Info    CBS   Plan: Start to process package watchlist.
  Info    CBS   Package Format: PSFX
  Info    CBS   Store corruption, manifest missing for package: Package_for_DotNetRollup~31bf3856ad364e35~amd64~~10.0.4330.6
  Error   CBS   Failed to resolve package 'Package_for_DotNetRollup~31bf3856ad364e35~amd64~~10.0.4330.6' [HRESULT = 0x800f0831 - CBS_E_STORE_CORRUPTION]
  Info    CBS   Mark store corruption flag because of package: Package_for_DotNetRollup~31bf3856ad364e35~amd64~~10.0.4330.6. [HRESULT = 0x800f0831 - CBS_E_STORE_CORRUPTION]
  Info    CBS   Failed to resolve package [HRESULT = 0x800f0831 - CBS_E_STORE_CORRUPTION]
  Info    CBS   Failed to check whether this is the real child: Package_for_DotNetRollup~31bf3856ad364e35~amd64~~10.0.4330.6 [HRESULT = 0x800f0831 - CBS_E_STORE_CORRUPTION]
  Info    CBS   Failed to collect affected dependent package for package: Microsoft-Windows-CoreEdition~31bf3856ad364e35~amd64~~10.0.19041.844 [HRESULT = 0x800f0831 - CBS_E_STORE_CORRUPTION]
  Info    CBS   Failed to process package watchlist. [HRESULT = 0x800f0831 - CBS_E_STORE_CORRUPTION]
  Info    CBS   Failed to plan execution. [HRESULT = 0x800f0831 - CBS_E_STORE_CORRUPTION]
  Error   CBS   Failed to process single phase execution. [HRESULT = 0x800f0831 - CBS_E_STORE_CORRUPTION]
  Info    CBS   WER: Generating failure report for package: Package_for_RollupFix~31bf3856ad364e35~amd64~~19041.985.1.6, status: 0x800f0831, failure source: CBS Other, start state: Absent, target state: Installed, client id: UpdateAgentLCU
  Info    CBS   Not able to query DisableWerReporting flag.  Assuming not set... [HRESULT = 0x80070002 - ERROR_FILE_NOT_FOUND]
  

• I have run the following:

  Sfc /ScanNow
    # Returns back nothing needs to be repaired
  
  ChkDsk /Scan
    # Nothing to be repaired
  
  Dism /Online /Cleanup-Image /RestoreHealth
  
    Error:
    Deployment Image Servicing and Management tool
    Version: 10.0.19041.844
  
    Image Version: 10.0.19042.844
  
    [==========================100.0%==========================]
    Error: 0x800f081f
  
    The source files could not be found.
    Use the "Source" option to specify the location of the files that are required to restore the feature.
    For more information on specifying a source location, see https://go.microsoft.com/fwlink/?LinkId=243077.
  
    The DISM log file can be found at C:\WINDOWS\Logs\DISM\dism.log
  

How do I troubleshoot this, as I have surfed the internet and no resources are found that can be used in this case?

https://answers.microsoft.com/en-us/windows/forum/all/uanble-to-install-windows-updates-error-code/ef2cc766-2243-4e50-94d8-ce7d16538242

try running the 'DISM.exe /Online /Cleanup-image /Scanhealth' as adm before the restore, seemed to work for me