Need to alter the 'From' email for the reports received. By default it is from 'admin@manthansystems.com.'
Modifying the 'From' email ID in arc.properties and re-caching changes will enable you to view the altered 'From' email ID only in case of Report Subscriptions and Alerts. However, in case of Schedule Email and Export Email, the email ID of the user with which you login to ARC, that particular email ID will be considered as 'From' email ID. (For e.g. if you login using ken from customer domain, then the 'From email ID will be kquick@microsoft.com ).