set alertMsg to "When Mail is configured to automatically check for new messages, certain Mail operations (such as mail rule processing, importing mailboxes, and asking if attachments should be downloaded when new messages arrive) may cause Mail to stop responding to script commands while processing large numbers of messages. " & return & return & "Due to a bug in this version of macOS, this script cannot ask Mail to temporarily disable this property while the script runs. Here is the error message generated by Mail: " & return & return & errorMessage & "(" & errorNumber & ")"