Unexpected icon description for Internet file attachments

File attachments included in messages that are received from the Internet have icon descriptions that are not the filename.

The sending party for the message used a MIME property called Content- Description described in RFC 1521 section 6.2 (shown below).

RFC 1521 All versions of Microsoft Exchange Server use the Content-Description MIME property to preserve the icon description through the Internet. The original filename is preserved and can be different than the icon description.

With the Microsoft Exchange client, when an attachment is inserted into a message, the default icon description is set to the filename. The user can right-mouse click on a file attachment in a message being composed, and choose "rename" to change the icon description. Changing the icon description does not change the filename.

If a remote system sends attachments and uses the Content-Description MIME property, all versions of Exchange Server will honor the provided data and use it as the icon description. If important information is communicated by means of the icon description field from other Internet sites or from Microsoft Exchange sites across Internet connectors, these descriptions will be lost.

If a remote system sends Content-Description MIME properties that are not meaningful, attempt to configure the remote system to suppress the sending of this MIME property. Mail received without this MIME property will have icon descriptions that are set to the filename.

Microsoft has confirmed this to be a problem in Microsoft Exchange Server version 5.0. This problem has been corrected in the latest U.S. Service Pack for Microsoft Exchange Server version 5.0. For information on obtaining the service pack, query on the following word in the Microsoft Knowledge Base (without the spaces):

Microsoft has added a new registry value to the Information Store service that allows an administrator the option of forcing the Information Store to ignore the Content-Description MIME property for incoming Internet mail.

WARNING: Using Registry Editor incorrectly can cause serious, system-wide problems that may require you to reinstall Windows NT to correct them. Microsoft cannot guarantee that any problems resulting from the use of Registry Editor can be solved. Use this tool at your own risk.

To enable this feature to ignore the Content-Description MIME property, perform the following steps:

1. Run Registry Editor (Regedt32.exe).
2. Go to the following key in the registry:

      HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\MSExchangeIs
                        \ParametersSystem\InternetContent\ 
   						

3. On the Edit menu, click Add Value and use the following entry:

         Value Name: IgnoreContentDescription
         Data Type:  REG_DWORD
         Value:      1

4. Exit the Registry Editor and restart the Information Store service for the change to take effect.

Setting the IgnoreContentDescription to 1 causes the Information Store to ignore the Content-Description MIME property when determining the icon description. To restore the behavior, either delete the registry value or set it to a value of 0 and restart the Information Store.

It is recommended that Microsoft Exchange administrators consider the ramifications of making this change. If important information is communicated via the icon description field from other internet sites (or Microsoft Exchange Sites across internet connectors), these descriptions will be lost.