In order to set those permissions for an account, you need to use an account which is a part of Organization Management group.
To do that with PowerShell, use this cmdlet:
Get-RoleGroup "Organization Management" | select membersIn case the given account is not a part of Organization Management group, the administrator needs to change that using this cmdlet:
Add-RoleGroupMember "Organization Management" -Member "<account name>"<account name> should stand for the name of the desired user.
The next step is granting full access permissions to mailboxes:
Get-Mailbox -ResultSize unlimited -Filter {(RecipientTypeDetails -eq 'UserMailbox') -and (Alias -ne 'Admin')} | Add-MailboxPermission -User admin@example.com -AccessRights fullaccess -InheritanceType all -AutoMapping:$falseThis will grant full access rights to all users for the account “admin@example.com”. The last parameter, “‑AutoMapping:$false” is not necessary, but is worth considering. It enables you to turn the Auto-mapping feature off. By default, if you do not include the parameter at all, it is set to $true. If it is not deactivated, admin’s Outlook will try to open all mailboxes in the company. This is rarely desirable and in case there are a lot of mailboxes, performance issues are to be expected. What is more, in many scenarios, users have experienced that removing Auto-mapping later on might prove to be problematic. Remember that if you do not include
