System User Role
The System User role is a predefined role that includes tasks that allow users to view basic information about the report server. It also includes support for loading a report in Report Builder. Report Builder is a client application that can process a report independently of a report server. The "Execute report definitions" task is intended for use with Report Builder. If you are not using Reporting Builder, you can remove this task from the System User role. The following table lists tasks that are included in the System User role definition.
Execute report definitions
Run a report without publishing it to a report server.
View report server properties
View properties that apply to the report server, such as the application name, whether My Reports is enabled, and report history defaults.
If you remove this task from the System User role, the Site Settings page is not available. Also, the application title is not displayed at the top of each page. By default, the title for Report Manager is "SQL Server Reporting Services."
View shared schedules
View shared schedules that are used to run reports or refresh a report.
If you remove this task from the System User role, users cannot select shared schedules to use with subscriptions and other scheduled operations.
The System User role can be used to supplement default security. You can include the role in new role assignments that extend report server access to report users. For more information, see Using Predefined Roles.