You may have received a message that contains a Level 1 e-mail security attachment file type. To help prevent the inadvertent spread of viruses, Microsoft Outlook compares the file type of each attachment in a received message with the file types on the e-mail security attachment file type list. If an attachment is a file type that can contain code that can run automatically without your consent, you cannot see or access the attachment.

Check the InfoBar (InfoBar: Banner near the top of an open e-mail message, appointment, contact, or task. Tells you if a message has been replied to or forwarded, along with the online status of a contact who is using Instant Messaging, and so on.) at the top of the message to see the name of the file attachment you are unable to access.

You have received a message that contains a Level 1 e-mail security attachment file type. To help prevent the inadvertent spread of viruses, Microsoft Outlook compares the file type of each attachment in a received message with the file types on the e-mail security attachment file type list. If the attachment is a file type that can contain code that can run automatically without your consent, you cannot see or access the attachment.

Check the InfoBar (InfoBar: Banner near the top of an open e-mail message, appointment, contact, or task. Tells you if a message has been replied to or forwarded, along with the online status of a contact who is using Instant Messaging, and so on.) at the top of the message to see the name of the file attachment you are unable to access.

Note  If you created a custom form that included a Level 1 file type in the message body, your attachment will not be visible once you save and close the form. The InfoBar will not show the name of the blocked file attachment because custom forms do not display the InfoBar.

Shortcuts with a file extension of .lnk or .url are Level 1 e-mail security attachment file types. To help prevent the inadvertent spread of viruses, Microsoft Outlook compares the file type of each attachment in a message you send with the Level 1 file types on the e-mail security attachment file type list. If the attachment file type is Level 1, recipients cannot see or access the attachment. Recipients can verify that this is why they are not seeing the shortcut by checking the message's InfoBar (InfoBar: Banner near the top of an open e-mail message, appointment, contact, or task. Tells you if a message has been replied to or forwarded, along with the online status of a contact who is using Instant Messaging, and so on.) to see if it displays the name of your shortcut. You can then send them a message with a text link instead of the shortcut.

You have received a message that contains a Level 1 e-mail security attachment file type. To help prevent the inadvertent spread of viruses, Microsoft Outlook compares the file type of each attachment in a received message with the file types on the e-mail security attachment file type list. If the attachment is a file type that can contain code that can run automatically without your consent, you cannot access the attachment. The InfoBar (InfoBar: Banner near the top of an open e-mail message, appointment, contact, or task. Tells you if a message has been replied to or forwarded, along with the online status of a contact who is using Instant Messaging, and so on.) will display the name of the file attachment you are unable to access.

You have received a message that contains a Level 1 e-mail security attachment file type. To help prevent the inadvertent spread of viruses, Microsoft Outlook compares the file type of each attachment in a received message with the file types on the e-mail security attachment file type list. If the attachment is a file type that can contain code that can be run automatically without your consent, you cannot access the attachment. The InfoBar (InfoBar: Banner near the top of an open e-mail message, appointment, contact, or task. Tells you if a message has been replied to or forwarded, along with the online status of a contact who is using Instant Messaging, and so on.) will display the name of the file attachment you are unable to access.

You might not have the intended recipient's certificate (certificate: A digital means of proving your identity. When you send a digitally signed message you are sending your certificate and public key. Certificates are issued by a certification authority, and like a driver's license, can expire or be revoked.) (public key (public key: The key a sender gives to a recipient so that the recipient can verify the sender's signature and confirm that the message was not altered. Recipients also use the public key to encrypt (lock) e-mail messages to the sender.)). Ask the recipient to send you a digitally signed message, and then add their certificate to Contacts.

There can be several reasons why the digital signature is not valid and not trusted. For example, the sender's certificate (certificate: A digital means of proving your identity. When you send a digitally signed message you are sending your certificate and public key. Certificates are issued by a certification authority, and like a driver's license, can expire or be revoked.) may have expired, it may have been revoked by the certificate authority (CA) (certificate authority (CA): An entity, similar to a notary public, that issues digital certificates, keeps track of who is assigned to a certificate, signs certificates to verify their validity, and tracks which certificates are revoked or expired.), or the server that verifies the certificate may be unavailable. Contact the sender of the message.

If you are using Rich Text Format for messages, and you send a digitally signed message, the message format is changed to HTML to help ensure correct processing of the security code. Some formatting may be lost in the conversion.

• If you receive the message: "The Security Policy you selected does not allow one of the certificates in this security profile to be used," it means that the certificate in your default security settings has expired or has otherwise become invalid, or that your security policy does not accept your certificate. If you have set your security options to use labels on every message you send, the automatic configuration will not automatically notify you that your certificate has become invalid. To makes sure that the automatic configuration notifies you of problems with your default certificates, on the Tools menu, click Options, and then click the Security tab. Click Settings, and then click Security Labels. In the Policy module list, click None. If your security system does not allow you to choose None, contact your system administrator to get the correct certificates for your system.

• If you receive the message: "Microsoft Outlook had problems encrypting this message because the following recipients had missing or invalid certificates, or conflicting or unsupported encryption capabilities," the most common cause is that you tried to send encrypted messages without having a copy of a valid certificate (certificate: A digital means of proving your identity. When you send a digitally signed message you are sending your certificate and public key. Certificates are issued by a certification authority, and like a driver's license, can expire or be revoked.) for the recipient. If you have multiple contacts for the recipient, you must send a message using the contact that has the certificate.

An S/MIME receipt (S/MIME receipt: An e-mail security feature used to request confirmation that a message was received unaltered and information about who opened the message and when it was opened. This verification information is returned as a message to your Inbox.) is not returned if either of the following is true:

• Your signature on the message is not verified by the recipient's security system. This happens if the certificate (certificate: A digital means of proving your identity. When you send a digitally signed message you are sending your certificate and public key. Certificates are issued by a certification authority, and like a driver's license, can expire or be revoked.) is not trusted.
• The recipient's messaging program does not support S/MIME.
• The recipient may have chosen not to send receipts when requested.

You have changed your default security setting from S/MIME to Exchange Server security. Security labels (security label: A secure e-mail feature that lets you add sensitivity labels, such as Internal Use Only, to the message header. Security labels in your organization are controlled by security policies set up by your e-mail administrator.), clear text signed messages, and S/MIME receipt (S/MIME receipt: An e-mail security feature used to request confirmation that a message was received unaltered and information about who opened the message and when it was opened. This verification information is returned as a message to your Inbox.) requests require that S/MIME (S/MIME: Secure Multipurpose Internet Mail Extensions (S/MIME) is a specification for secure e-mail messages that uses the X.509 format for digital certificates and uses various encryption algorithms such as 3DES.) be your default security format. On the Tools menu, click Options and then click the Security tab. Click the Settings button and then in the Cryptographic format list, click S/MIME.

• You must have a security policy module installed. For more information, contact your system administrator.
• You must digitally sign the message. In the message, on the File menu, click Properties, and then click the Security tab. Select the Add digital signature to message check box.
• If the privacy mark, classification, or other settings are not available, it may be because of settings specific to the policy module. For more information, contact your system administrator.
• You must be using S/MIME (S/MIME: Secure Multipurpose Internet Mail Extensions (S/MIME) is a specification for secure e-mail messages that uses the X.509 format for digital certificates and uses various encryption algorithms such as 3DES.) as your default security format. To change your default security format, on the Tools menu, click Options and then click the Security tab. Click Settings, and then in the Cryptographic format list, click S/MIME.

• Your server may be unavailable. Send a test message addressed to yourself to see if your server is working.
• You may not have permission to write to the Global Address List (Global Address List: The address book that contains all user, group, and distribution list e-mail addresses in your organization. The administrator creates and maintains this address book. It may also contain public folder e-mail addresses.). For more information, contact your administrator.
• The security policy you are using may not allow the Publish to GAL button to appear. If the button is unavailable, contact your Microsoft Exchange server administrator.

• You must be using Microsoft Windows 2000 or later.

• You must have a valid security profile, including a valid certificate, to send an S/MIME receipt (S/MIME receipt: An e-mail security feature used to request confirmation that a message was received unaltered and information about who opened the message and when it was opened. This verification information is returned as a message to your Inbox.) request.

• If you are using an Internet e-mail account, such as POP3, an S/MIME receipt request is not sent until you click Send/Receive on the Microsoft Outlook toolbar.

• Security labels (security label: A secure e-mail feature that lets you add sensitivity labels, such as Internal Use Only, to the message header. Security labels in your organization are controlled by security policies set up by your e-mail administrator.) appear only on messages sent and received by users who use Microsoft Windows Millennium Edition (Me) or later. If you send a message with a security label to a recipient who uses a previous version of Windows that doesn't support this feature, the recipient will not be able to open the message.
• If recipients do not have the appropriate policy module, they may not be able to open the message.

You may also receive error messages while synchronizing or when sending e-mail from some Handheld PCs.

Your security zone setting is set to the highest security level by default, which disables all active content in HTML messages.