Microsoft Outlook now automatically selects an optimal encoding for outgoing mail messages. This feature increases the likelihood that when you send a message with Outlook 2002, the receiver will see all the characters rendered properly, even if they run older e-mail programs.

Outlook scans the entire text of the outgoing message to determine a minimal popular encoding for the message. Outlook selects an encoding that is capable of representing all the characters, and that is optimized so that the majority of the receiving e-mail programs can interpret and render the content properly.

This table shows a few examples of how this works.

This works for users sending Internet mail through the POP/SMTP or IMAP transport, or for messages sent through Microsoft Exchange Server 5.5 SP 1 or higher.

 Note    This Outlook feature requires that users sending the message have Microsoft Internet Explorer 5.5 installed.

With previous versions of Outlook, users had to manually overwrite format encoding to choose the most appropriate encoding for an individual message. Users are no longer required to do this.

Disabling Auto-Select outbound encoding

Microsoft Outlook automatically enables Auto-Select outbound encoding once Internet Explorer 5.5 or higher is installed. You can disable Auto-Select outbound message encoding with a registry key. For the following subkey, set Autodetect_CodePageOut to 0:

HKEY_CURRENT_USER\Software\Microsoft\Office\10.0\Outlook\Options\MSHTML\International

The value is a DWORD.

If the registry subkey is not found, if there is no value set for the registry subkey, or if the value is set to 1, Auto-Select is enabled (as long as Internet Explorer 5.5 is installed on the user's computer).

To set this value through the user interface, go to the Tools |Options, Mail Format tab. In the Message format: section, click International Options, then select Auto-Select encoding for outgoing messages.

Setting default encoding for outbound messages

You can set a registry key to establish a default encoding for outbound e-mail messages. This encoding is used for all outbound messages if Auto-Select encoding is not enabled. This encoding is also used as the preferred encoding if the Auto-Select encoding algorithm finds multiple suitable encodings for the message. By default, Outlook sets preferred encoding to a popular Internet encoding corresponding to the active Windows code page of the user's computer. For example, Outlook specifies Western European (ISO) when running on Western European Latin1 Windows code page 1252.

For example, to set the default code page to be used for message encoding to "Western European (ISO)":

HKEY_CURRENT_USER\Software\Microsoft\Office\ 10.0\Outlook\Options\MSHTML\International\ Default_CodePageOut=00006faf

This value is a DWORD. (See the table in the next section for a list of encodings and corresponding code pages.)

To set this value through the user interface, go to Tools, Options, Mail Format. In the Message format: section, click International Options. Then, in the drop-down list for Preferred encoding for outgoing messages, select the encoding that you prefer.

Outlook encoding support

Outlook supports the following encodings when sending and receiving e-mail messages.

 Note    For Auto-Select encoding to work properly, you must make sure that appropriate international support (NLS files and fonts) is installed on users' computers. For more information about enabling international support, see Preparing Users' Computers for International Use.

By default, Auto-Select considers for detection all encodings marked "Yes" in the table below. All encodings in the list below are valid values to set as the "Preferred encoding for outgoing messages" by using the registry subkey Default_CodePageOut, which is described above.