Set Calendar Permissions in Exchange Online using Powershell

I’ve created a script for setting calendar permissions on a list of users according to the CSV file format. You can find additional details by referencing the script’s help information and the included screenshots.

The script will first attempt to connect to Office365. Please supply the correct username and password with the necessary permissions to run the script. As a best practice, start by including 2-3 users in the UserList.csv file before applying the script to all users to ensure successful execution.

UserList.csv File Format (Please make sure to keep the same headers (Mailbox,User, AccessRights) as in the Below file:

Example I

Dot Source the Script 

PS> . D:\Scripts\Set-CalendarPermission.ps1

PS> Get-Help Set-CalendarPermissions

Set-CalendarPermission.ps1

Function Set-CalendarPermission {
    <#
    .SYNOPSIS
    Apply/SET the Calendar Permissions on a list of mailboxes using permissions mentioned in a CSV file.

    .DESCRIPTION
    This function sets Calendar Permissions for multiple mailboxes based on a CSV file.

    .NOTES
    Name       : Set-CalendarPermission
    Author     : Jatin Makhija
    Version    : 1.0.0
    DateCreated: 30-Nov-2019
    Blog       : https://techpress.net

    .LINK
    https://techpress.net

    .EXAMPLE
    PS> Set-CalendarPermission -CSVFilePath <CSV File Path>

    For example:
    Set-CalendarPermission -CSVFilePath "C:\Temp\UserList.csv"

    .EXAMPLE
    Set-CalendarPermission

    #>

    [cmdletBinding()]
    param(
        [parameter(Mandatory = $true, Position = 0, HelpMessage = "Please enter the path to the CSV file.")]
        [string]$CSVFilePath
    )

    Write-Host "Connecting to Office365" -ForegroundColor Blue -BackgroundColor White
    Write-Host "Please provide your Office365 Global Administrator UserName and Password or a user with appropriate rights on EXO to update users' Calendar Permissions" -ForegroundColor Blue -BackgroundColor White

    Try {
        $ExCred = Get-Credential
        $Session = New-PSSession -ConfigurationName Microsoft.Exchange -ConnectionUri https://ps.outlook.com/powershell/ -Credential $ExCred -Authentication Basic -AllowRedirection
        Import-PSSession $Session
        Write-Host "Connection to Office365 established" -ForegroundColor Blue -BackgroundColor White
    }
    Catch {
        Write-Warning "User not authenticated / User credentials not accepted / User credentials not provided"
        Write-Warning $_
        break
    }

    $csvData = Import-Csv $CSVFilePath -Header Mailbox, User, AccessRights

    foreach ($row in $csvData) {
        $MailboxName = $row.Mailbox
        $UserName = $row.User
        $AccessRights = $row.AccessRights

        if (-not (Get-Aduser -Filter { DisplayName -eq $MailboxName }).Enabled) {
            Write-Host "$MailboxName is a disabled user account in AD" -ForegroundColor DarkYellow
        } else {
            if (Get-Mailbox $MailboxName -ErrorAction SilentlyContinue) {
                Try {
                    $userList = Get-MailboxFolderPermission -Identity "$($MailboxName):\Calendar" | Select -ExpandProperty User | Select -ExpandProperty DisplayName

                    if ($userName -in $userList) {
                        $userRights = Get-MailboxFolderPermission -Identity "$($MailboxName):\Calendar" -User "$userName" | Select -ExpandProperty AccessRights

                        if ($userRights -eq $AccessRights) {
                            Write-Host "User $UserName already has $userRights on $MailboxName. No action required." -ForegroundColor Green
                        } else {
                            Write-Host "User $UserName already has permission assigned. Existing Permission: $userRights New Permission: $AccessRights" -ForegroundColor Yellow
                            Write-Host "Setting permissions as per the CSV file to $AccessRights"
                            Set-MailboxFolderPermission -Identity "$($MailboxName):\Calendar" -User "$UserName" -AccessRights $AccessRights
                            Write-Host "Permission $AccessRights on User $UserName set." -ForegroundColor Black -BackgroundColor White
                        }
                    } else {
                        Write-Host "User $Username is not assigned permission on $MailboxName. Adding permission now."
                        Write-Host "Processing ADD command for User $MailboxName"

                        if (Get-Mailbox $UserName -ErrorAction SilentlyContinue) {
                            Add-MailboxFolderPermission -Identity "$($MailboxName):\Calendar" -User "$UserName" -AccessRights $AccessRights
                        } else {
                            Write-Host "$UserName's mailbox does not exist. Can't add the permission." -ForegroundColor Gray
                        }
                    }
                } Catch {
                    Write-Warning $_
                }
            } else {
                Write-Host "$MailboxName's mailbox does not exist." -ForegroundColor Gray
            }
        }
    }

    Write-Host "Removing PSSession $Session" -ForegroundColor Blue -BackgroundColor White
    Remove-PSSession $Session
}