When you use Windows Mail on a computer that is running Windows Vista, some messages may become stuck in the Outbox. You cannot send or delete these messages. Every time that you close Windows Mail, you are prompted that there are unsent messages in your Outbox. There might also be messages that are stuck in other folders, such as the Inbox or Deleted folders, that you cannot remove. The first step that you should take to resolve this problem is to download and install the following update for Windows Vista: Download the hotfix from Microsoft. If neither the hotfix nor the article solve your problem, please contact your computer's manufacturer for support.