Office 365 - Allow delegates to view private items in a shared mailbox using PowerShell

Office 365 - How to use Exchange Online PowerShell to grant delegates permissions to view private items in a shared mailbox using Outlook 

Grant delegates permissions to view private items using PowerShell

Messages with the sensitivity tag set to private can't be viewed in shared mailboxes unless you grant delegates permissions to ViewPrivateItems

Connect to Exchange Online

Connect-ExchangeOnline -UserPrincipalName [email protected] 

Grant mailbox Full Access permissions

You have to give Full Access to the shared mailbox so it appears in Outlook

Add-MailboxPermission -Identity [email protected] -User [email protected] -AccessRights FullAccess 

PowerShell Add-MailboxFolderPermission and Set-MailboxFolderPermission

Use Add-MailboxFolderPermission to add a new delegate to the shared mailbox and Set-MailboxFolderPermission to change permissions for an existing delegate

Add new user to mailbox with Add-MailboxFolderPermission ViewPrivateItems

Add-MailboxFolderPermission -Identity [email protected]:\Calendar -User [email protected] -AccessRights Editor -SharingPermissionFlags Delegate,CanViewPrivateItems 

Change existing users mailbox permissions with Set-MailboxFolderPermission ViewPrivateItems

Set-MailboxFolderPermission -Identity [email protected]:\Calendar -User [email protected] -AccessRights Editor -SharingPermissionFlags Delegate,CanViewPrivateItems 

List mailbox folder permissions for a user

Get-MailboxFolderPermission -Identity [email protected]:\Calendar -User [email protected] 

Remove mailbox folder permissions for a user

Remove-MailboxFolderPermission -Identity [email protected]:\Calendar -User [email protected] 

Viewing delegate permissions in Outlook

File - Account Settings - Delegate Access

Reference:

Private items aren't displayed in a shared mailbox in Outlook
https://learn.microsoft.com/en-us/exchange/troubleshoot/user-and-shared-mailboxes/private-items-not-display

by Author