To install, run the following command from the location containing setup.exe and your configuration.xml file: . This will perform the installation using the local source files.
If you require absolute, permanent offline environment validation, you must look into volume license models like Office LTSC (Long Term Servicing Channel), which utilizes Key Management Services (KMS) or Multiple Activation Keys (MAK) rather than web-tied 365 user profiles. microsoft office 365 offline installer