Mailbox permissions

Hi @Glenn Maxwell

Thank you for sharing your concern. 

You could use this script: 

Connect-Exchange Online

$RoomMailbox = "your room mailbox"   
$CsvPath     = "your CSV path"  
# ============================== 
# Import users (robust method) 
# ============================== 
if (-not (Test-Path $CsvPath)) { 
    Write-Error "CSV file not found: $CsvPath" 
    return 
} 
  
# Read all lines, skip header/empty lines, extract email addresses 
$Users = Get-Content $CsvPath -Encoding UTF8 | 
         Where-Object { $_ -match '@' -and $_.Trim() -ne '' } | 
         ForEach-Object { $_.Trim() } 
  
if ($Users.Count -eq 0) { 
    Write-Error "No email addresses found in the CSV file!" 
    return 
} 
  
Write-Host "Found $($Users.Count) users. Starting to assign permissions on room mailbox: $RoomMailbox" -ForegroundColor Cyan 
Write-Host "" 
  
foreach ($User in $Users) { 
    Write-Host ">>> Processing: $User" -ForegroundColor Yellow 
  
    try { 
        # 1. Full Access 
        Add-MailboxPermission -Identity $RoomMailbox ` 
                              -User $User ` 
                              -AccessRights FullAccess ` 
                              -InheritanceType All ` 
                              -AutoMapping $false ` 
                              -ErrorAction Stop | Out-Null 
        Write-Host "  [OK] Full Access" -ForegroundColor Green 
  
        # 2. Send As 
        Add-RecipientPermission -Identity $RoomMailbox ` 
                                -Trustee $User ` 
                                -AccessRights SendAs ` 
                                -Confirm:$false ` 
                                -ErrorAction Stop | Out-Null 
        Write-Host "  [OK] Send As" -ForegroundColor Green 
  
        # 3. Send on Behalf 
        Set-Mailbox -Identity $RoomMailbox ` 
                    -GrantSendOnBehalfTo @{Add=$User} ` 
                    -ErrorAction Stop | Out-Null 
        Write-Host "  [OK] Send on Behalf" -ForegroundColor Green 
  
        # 4. Calendar Editor 
        Add-MailboxFolderPermission -Identity "$RoomMailbox`:\Calendar" ` 
                                    -User $User ` 
                                    -AccessRights Editor ` 
                                    -ErrorAction Stop | Out-Null 
        Write-Host "  [OK] Calendar Editor" -ForegroundColor Green 
    } 
    catch { 
        Write-Warning "  Failed for $User : $($_.Exception.Message)" 
    } 
  
    Write-Host "" 
} 
  
Write-Host "Completed!" -ForegroundColor Cyan 

Please give it a try and let me know if this helps. 

If you have any additional concerns, feel free to comment below. I would be more than happy to assist. 

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