According to the Prism Central Guide regarding Reporting, predefined system reports (such as Cluster Efficiency, Environment Summary, etc.) are built-in templates provided by Nutanix. The documentation explicitly states that while administrators can view and run these reports, they cannot delete or modify (Edit) the structure of these predefined reports directly.

However, the valid action an administrator can perform on a predefined report is to Schedule it. Scheduling allows the report to run automatically at specified intervals and email the results to recipients. If modification is required, the administrator must first clone the predefined report to create a custom copy, which can then be edited; the original remains locked.