If the file is truly missing from the Office folders, perform an Online Repair Control Panel Uninstall a Program > select Microsoft 365/Office > Stack Overflow Alternative: Late Binding
If you need a concise remediation plan (Windows Office): run an Office Online Repair first; if that fails, ensure Outlook is installed for your SKU and reinstall Outlook/Office; convert code to late binding as a temporary fix. microsoft outlook 16.0 object library dll download