XCLN: Internet Options Tab Missing from Send Options Dialog Box

When you go to Properties of a message in any of the Microsoft Exchange clients or Outlook clients and click Send Options, no Internet tab will appear on the dialog box. Without this tab, the type of encoding format for attachments is no longer configurable.

Due to a registry limitation, the maximum number of message types (for example, SMTP, MS, EX, X.400, and so on) that can be stored by any given client is hard-coded to 16. If you have more than 16 unique message types, some of them will not be downloaded to the client's registry. These message types are stored alphabetically, and this problem is only seen when 16 message types alphabetically come before SMTP. For example, if a Microsoft Exchange organization has 16 unique custom message types that begin with the letter "F", the SMTP option information will not be stored in the client's registry and the Internet tab will not be shown in the Send Options dialog box.

To resolve this problem, obtain the latest service pack for Exchange Server version 5.5. For more information, please see the following article in the Microsoft Knowledge Base:

Microsoft has confirmed this to be a problem in Microsoft Exchange Server version 4.0. We are researching this problem and will post additional information here in the Microsoft Knowledge Base as it becomes available.

Microsoft has confirmed this to be a problem in Microsoft Exchange Server version 5.0.

A supported fix is now available, but has not been fully regression-tested and should be applied only to systems experiencing this specific problem. Unless you are severely impacted by this specific problem, Microsoft recommends that you wait for the next service pack that contains this fix. Contact Microsoft Technical Support for more information.

This fix has been posted to the following Internet location:


Microsoft has confirmed this to be a problem in Microsoft Exchange Server version 5.5. This problem has been corrected in the latest U.S. service pack for Microsoft Exchange Server version 5.5. For information on obtaining the service pack, query on the following word in the Microsoft Knowledge Base (without the spaces):
However, in some cases, you may still experience the symptoms described above after applying the fix. Microsoft has confirmed this to be a problem in newer builds of the Microsoft Exchange Server version 5.5 information store. This problem has been corrected in Exchange Server 5.5 Service Pack 2.