Microsoft-windows-netfx3-ondemand-package.cab -extra

"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."

The presence of this file usually signals a specific problem: Microsoft-windows-netfx3-ondemand-package.cab -Extra

: Microsoft sometimes provides multiple .cab files for the same feature, such as language-specific "Extra" packs or architecture-specific versions (e.g., ~amd64~en-US~.cab ). "The source files could not be found