Use case: Use this procedure to create a report that identifies all mailbox delegation – such as Send As, Send on Behalf, or Full Access permissions – across selected mailboxes. This helps you review and manage who has access to other users’ mailboxes.
About report templates
A report template defines what the report shows (type) and who it targets (scope). Once a template is created, it can be reused to generate new reports or review results from previous runs. The scope of an existing template can be updated at any time, but the type cannot be changed.
To create a report that identifies delegated mailbox access, do the following:
- Go to Entra ID, right-click Reports, and select New Report Template.
- Set the Category to Mailboxes, set the Type to DelegatedAccess, and click Next.
- Configure the Scope to narrow the focus of the report or leave it blank to include all mailboxes, then click Create.
- Click Run to execute the report immediately.
- Once the report completes, double-click it to view and filter the results.
This report type (Mailboxes → DelegatedAccess) may take several minutes or even hours to complete in very large environments (10,000+ mailboxes).
To search and filter the report
- Use the Search field to search across all report columns in real time.
- To filter on a specific column, use
[ColumnName]=[search phrase]. - For column names containing multiple words, omit the spaces. You can shorten a column name as long as you include enough characters to identify it uniquely.
- For example, use
AccessRight=FullAccessor the shorteracc=fulto find FullAccess permissions. - Combine searches across multiple columns, e.g.
acc=ful typ=user, to identify UserMailbox objects with FullAccess permissions.
To export the report data
- Select the rows you wish to export (CTRL + A to select all).
- Press CTRL + C to copy and CTRL + V to paste into Excel, Notepad, or another tool.
Other Report Types
How to Create a Report: Disabled Users With Microsoft 365 Subscriptions
How to Create a Report: Identify Core Microsoft 365 Workloads Not Being Used
How to Create a Report: Inactive Users With Microsoft 365 Subscriptions
How to Create a Report: User MFA Configuration and Readiness
How to Create a Report: Mailbox and Archive Sizes
