I installed MikTex with the basic-miktex-2.9.4521.exe installer. Following the documentation at
I use the --install-root switch to choose a location to install some extra packages but it fails
"C:\Program Files (x86)\MiKTeX 2.9\miktex\bin\mpm" --install-some=packages.txt --install-root=C:\Work
mpm: --install-root=C:\Work: unknown option
I think that this switch used to work in the past.