0x800F0906 in DISM: Windows cannot download the repair source files
0x800F0906 means DISM could not reach Windows Update for repair files. Point /RestoreHealth at a mounted ISO of the same build to finish the repair offline.
0x800F0906 and 0x800F081F: .NET Framework 3.5 Will Not Enable on Windows
0x800F0906 means Windows cannot fetch the .NET 3.5 payload. Supply a matching install source with DISM and bypass the WSUS policy that blocks feature files.