XFOR: POP3 Clients and Mail Conversion Failures

• Microsoft Exchange Server version 5.0

IMPORTANT: This article contains information about editing the registry. Before you edit the registry, make sure you understand how to restore it if a problem occurs. For information on how to do this, view the "Restoring the Registry" online Help topic in Regedit.exe or the "Restoring a Registry Key" online Help topic in Regedt32.exe.

SUMMARY

During the course of normal use, Microsoft Exchange Server may accept a corrupted incoming mail message from an outside source (another Exchange Server computer, a client, an NNTP newsfeed, and so on).

When POP3 clients download these messages from the Microsoft Exchange Server computer, a content conversion failure may occur. If a content conversion failure occurs, Microsoft Exchange Server returns an error message to the client and marks the failed message as non-downloadable. The failed message and all other messages in the user's Inbox cannot be downloaded. However, the message may still be readable by Microsoft Exchange Client, so an administrator can use Microsoft Exchange Client to recover the message for the POP3 user.

If a POP3 user receives a content conversion error, administrators are encouraged to send the failed message to Microsoft Technical Support. If content conversion failures occur frequently, administrators can also edit the registry so POP3 users can continue to download messages after a content conversion error is returned. Any failed messages are hidden from POP3 clients, but still exist in the user’s Inbox, so they can be downloaded using Microsoft Exchange Client.

MORE INFORMATION

WARNING: Using Registry Editor incorrectly can cause serious problems that may require you to reinstall Windows. Microsoft cannot guarantee that problems resulting from the incorrect use of Registry Editor can be solved. Use Registry Editor at your own risk.

For information about how to edit the registry, view the "Changing Keys And Values" online Help topic in Registry Editor (Regedit.exe) or the "Add and Delete Information in the Registry" and "Edit Registry Data" online Help topics in Regedt32.exe. Note that you should back up the registry before you edit it.

To modify the registry setting:

1. Start Registry Editor (Regedt32.exe or Regedit.exe as appropriate for your version of Windows NT).

2. Go to the following key in the registry:

         HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services
         \MSExchangeIS\ParametersSystem
   

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

         Value Name: POP3 Performance
         Data Type:  REG_DWORD
         Value:      2
   
   

4. Exit Registry Editor.