Mailbox Folder Permissions Report

The below script will gather all the recipient accounts, then gather anyone that has access to the Calendar, Contacts, or root folder

Prerequisites

This script makes use of the ExchangeOnlineManagement module.

Script

Copy and paste the whole block into PowerShell, or a ps1 file, then run it.

$AllUsers = Get-Recipient -ResultSize:Unlimited
$UserFolders = @(":\",":\Calendar",":\Contacts")
$allUserDetails = @()
$Counter=0
ForEach ($user in $allusers) {
    $Counter++
    Write-Progress -Id 0 -Activity "Processing User" -PercentComplete (($Counter / $allusers.count) * 100)
    foreach ($Folder in $UserFolders) {
        $UPNFolder = ($user.ExchangeGuid).ToString() + $Folder
        $FolderPerms = Get-MailboxFolderPermission -Identity $UPNFolder
        if ($null -ne $FolderPerms) {
            $CounterA=0
            $allUserDetails = foreach ($entry in $FolderPerms) {
                $CounterA++
                Write-Progress -Id 1 -ParentId 0 -Activity "Processing Folder" -PercentComplete (($CounterA / $FolderPerms.count) * 100)
                $Properties =  [ordered]@{
                    'Identity'=$entry.Identity;
                    'FolderName'=$entry.FolderName;
                    'User'=$entry.User;
                    'AccesRights'=$entry.accessRights -join ";";
                    'SharingPermissionFlags'=$entry.SharingPermissionFlags
                }
                New-Object -TypeName PSObject -Property $Properties
            }
        }
    }
}
 
$allUserDetails | export-csv C:\Temp\All-Calendar-Contacts-Details.csv -NoTypeInformation