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Attachment file types blocked by Outlook
There are two levels of attachment security. Access to level 1 files is blocked and can't be changed. When you receive an attachment with a level 2 file type, you will be prompted to save the file to your hard disk. If you use Microsoft Exchange Server, your administrator can add and remove file types for both levels of e-mail security. If a file type is added to both levels, it will be treated as a level 1 file type.
By default, Microsoft Outlook blocks attachment files ( such as .bat, .exe, .vbs, and .js) that can contain viruses. You cannot see or access the attachment. Your Inbox will display the paperclip icon in the Attachment column to let you know that the message has an attachment, and you will see a list of the blocked attachment files in the InfoBar at the top of your message.