What is the purpose of administrative installation initiated using msiexec /a?

Question

Windows Installer technology supports administrative installation. The command line for initiating administrative installation is: \'msiexec /a setup.msi\'.

Answer 1

If you have a per-user setup and a system that disallows user installations through e.g. group policy then the user will be able to install from the msi created in the target folder by the administrative install. Its a way of authorising software to be installed.