This how‑to shows how to maintain control over Exchange Online mailbox permissions.
This is especially useful during employee or contractor onboarding, role changes, or offboarding.
Operators are only able to view and manage mailboxes that are part of their defined V-Tenant scope.
Step 1: review
- Search for “User mailbox” under “Reports”.
- Alternatively, go to “Reports > Security > User mailbox security”.
- A table listing all delegates will be displayed. Use the column filters to find the users you are targeting.
The data includes details such as recipient type, company country, and department details for both the delegated mailbox and the delegate to help identify anomalies.
For example:
- During role changes, users may retain mailbox access they should no longer have.
- Filter with
Type of User with Access = SharedMailbox. This often reveals old or decommissioned user accounts (e.g., user mailboxes migrated to shared) that still have delegate permissions.
Step 2: management
- Go to “Actions > Management actions”
- Under the “Filter assistant”, check the “Mailbox” option. This will reveal a list of possible management actions. These actions provide quick and comprehensive management of mailbox permissions for managing mailbox permissions.
