The source files could not be found. Error 0x800f0906.
This infamous error, that may be returned when installing a Windows Server feature, indicates the inability of the installer to access the source files or the correct version of the source files. As per this blog, even specifying the installation media may not resolve the problem, as the installer may be expecting a different version of the binaries. Allowing updates from WSUS may work, but in my experience this isn’t usually the case.
There are several options for resolving this problem, e.g.:
Install-WindowsFeature AD-Domain-Services -Source Online Install-WindowsFeature AD-Domain-Services -Source wim:"X:\sources\install.wim":2 Install-WindowsFeature AD-Domain-Services -Source "X:\sources\sxs\"
Obviously, adjust the drive letter to the appropriate letter of your mounted installation ISO.
One particularly troublesome feature is AD Domain Services, for which I have found that the only solution is to provide access to a copy of the SxS store of the same binary version, e.g. the SxS store on another similarly-patched server. Using
Install-WindowsFeature accesses network shares using the server’s context, which generally won’t have access to an admin share on a DC, so the
Enable-WindowsOptionalFeature cmdlet must be used, which uses the current user’s context:
Enable-WindowsOptionalFeature -Online -FeatureName DirectoryServices-DomainController -All -Source "\\DC01\C$\Windows\WinSxS\"