DISM error 0x800f081f "The source files could not be found": give Windows a matching source

1. Look at the state first

DISM /Online /Cleanup-Image /CheckHealth
DISM /Online /Cleanup-Image /ScanHealth

CheckHealth is quick, and ScanHealth takes a while. The details are in C:\Windows\Logs\DISM\dism.log, and in C:\Windows\Logs\CBS\CBS.log, where the failing package is usually named.

2. Try Windows Update

With no /Source, DISM downloads from Windows Update. On a machine pointed at WSUS, that often fails, because WSUS usually doesn’t hold those repair files. You can allow the direct route with a policy: Computer Configuration → Administrative Templates → System → “Specify settings for optional component installation and component repair”, and enable Download repair content … directly from Windows Update.

The same setting in the registry, for a quick test:

$key = 'HKLM:\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\Servicing'
New-Item -Path $key -Force | Out-Null
Set-ItemProperty -Path $key -Name RepairContentServerSource -Value 2 -Type DWord
gpupdate /force

Then run /RestoreHealth again. Undo it afterwards if you manage this by policy.

3. Use an ISO that matches

Find your exact version:

winver
Get-ComputerInfo -Property WindowsProductName, OsBuildNumber, OsHardwareAbstractionLayer
(Get-ItemProperty 'HKLM:\SOFTWARE\Microsoft\Windows NT\CurrentVersion').DisplayVersion

Get an ISO of that version in the same language and architecture, and mount it. Windows assigns a drive letter, E: in these examples. Installation media has one of two files:

• sources\install.wim: use wim:
• sources\install.esd: use esd:

Find the index of your edition:

Get-WindowsImage -ImagePath "E:\sources\install.wim" | Format-Table ImageIndex, ImageName

DISM /Online /Cleanup-Image /RestoreHealth /Source:wim:E:\sources\install.wim:3 /LimitAccess

/LimitAccess keeps DISM off Windows Update, so you see whether this source works by itself.

The prefix matters. Without it, DISM treats the path as a folder and doesn’t read the file, and you get the same error.

4. Still failing: the source is too old

An ISO from the release date doesn’t contain the fixes installed since, so the files DISM wants may not be in it. Two ways out:

Get a newer ISO. Current media from Microsoft includes recent updates.

Update the machine first. Install the latest cumulative update, by hand from the Microsoft Update Catalog if Windows Update is broken. Then try again, using the newer ISO if you have one.

Also, a known source of this is a failed update stuck in a pending state. See whether anything is waiting, and if so, restart first:

DISM /Online /Get-Packages /Format:Table | Select-String 'Pending|Staged'

5. The feature case

The same error appears when installing a feature that was removed from disk, with .NET Framework 3.5 being the classic:

DISM /Online /Enable-Feature /FeatureName:NetFx3 /All /Source:E:\sources\sxs /LimitAccess

The source here is the sources\sxs folder, with no wim: prefix. Or with PowerShell:

Install-WindowsFeature NET-Framework-Core -Source E:\sources\sxs

6. Then run SFC

DISM repairs the image, and sfc uses that to repair your running system. So the order is DISM, then SFC:

sfc /scannow

If repairs keep failing and you’ve tried a fresh, matching ISO, an in-place upgrade from that ISO reinstalls Windows while keeping apps and data. Take a backup first. If the disk itself is failing, repair won’t last: run chkdsk C: /scan.