Details
Reports provide information about your organization’s usage data. These reports, by default, display information with identifiable names for groups, sites, and users.
Steps to revert this change
Global administrators can revert this change for their tenant and show identifiable user information if their organization's privacy practices allow it. It can be achieved in the Microsoft 365 admin center by following these steps:
In the admin center, go to the Settings > Org Settings > Services page.
Select Reports.
Uncheck the statement Display concealed user, group, and site names in all reports, and then save your changes.
It may take 24-72 hours for these changes to take effect on the reports in the reports dashboard. This setting also applies to the Microsoft 365 usage reports in Microsoft Graph and Power BI and the usage reports in Microsoft Teams Admin center. Showing identifiable user information is a logged event in the Microsoft 365 compliance center audit log.
For more information, visit Microsoft's activity report documentation.