XADM: Exchange Server Administrator Cannot Display More Than 65535 Public Folders

If you examine the Instances tab in the properties of the public information store and there are over 65,535 public folders, the following error message may be displayed:

This issue can occur because the Exchange Server Administrator program relies on MAPI to retrieve information about public folders. MAPI architecture only allows 65,535 rows in a table. If more than 65,535 public folders exist, the table is unable to hold all of the entries and the error message in the "Symptoms" section of this article may be displayed.

To resolve this problem, obtain the latest service pack for Exchange Server 5.5. For additional information, click the following article number to view the article in the Microsoft Knowledge Base:

Microsoft has confirmed that this is a problem in Microsoft Exchange Server version 5.5. This problem was first corrected in Exchange Server 5.5 Service Pack 4.

After this fix is applied, the Exchange Server Administrator program generates a dialog box that informs you that more than 65,535 public folders exist but only the first 65,535 are displayed. The following is sample text from the dialog box:
WARNING: If you use Registry Editor incorrectly, you may cause serious problems that may require you to reinstall your operating system. Microsoft cannot guarantee that you can solve problems that result from using Registry Editor incorrectly. Use Registry Editor at your own risk.

To add the registry key mentioned in the dialog box:

1. Start the Registry Editor (Regedt32.exe).
2. Locate the following key in the registry:
   HKEY_Current_User\Software\Microsoft\Exchange\MSExchAdminCommon
3. On the Edit menu, click Add Value, and then add the following registry value:
   Value Name: Public Folder Skip Count
   Data Type: REG_DWORD
   Value: number of folders to skip
   This registry value sets the number of public folder entries to skip from the beginning of the list. For example, if the dialog box text indicates a total of 80,004 entries, to display the additional entries set the value to 14469 (80,004 total entries - 65,535 base entries). This allows public folder entries 14,469 through 80,004 to be displayed.
4. Quit the Registry Editor.