Microsoft KB Archive/297976

= Outlook Mobile Access for Exchange 5.5 Reports &quot;All CDO Sessions Are In Use (Default Is 300)&quot; =

Article ID: 297976

Article Last Modified on 10/28/2006

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APPLIES TO


 * Microsoft Mobile Information Server 2001 Enterprise Edition

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This article was previously published under Q297976



IMPORTANT: This article contains information about modifying the registry. Before you modify the registry, make sure to back it up and make sure that you understand how to restore the registry if a problem occurs. For information about how to back up, restore, and edit the registry, click the following article number to view the article in the Microsoft Knowledge Base:

256986 Description of the Microsoft Windows Registry



SYMPTOMS
When using Outlook Mobile Access for Microsoft Exchange Server 5.5, you may be unable to browse your mailbox or a specific folder in your mailbox during high server usage.

In the Application log, you may see events that contain the following error message:

All CDO sessions are in use (default is 300)



CAUSE
This problem occurs because the number of CDO sessions that are open by Outlook Mobile Access has exceeded the default, which is 300.



RESOLUTION
To resolve this problem, increase the default number of Active CDO sessions.

On the Mobile Information Server on which the Outlook Mobile Access for Exchange 5.5 component is installed, increase the value of the following registry key: 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.

 Start Registry Editor (Regedt32.exe). Locate the MaxActiveCDOSessions_Count value under the following key in the registry:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Oma55\CDOSessions

 On the Edit menu, click String, type a value that is > 300, and then click OK. Quit Registry Editor.



STATUS
Microsoft has confirmed that this is a problem in the Microsoft products that are listed at the beginning of this article.

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MORE INFORMATION
Microsoft Outlook Mobile Access for Exchange 5.5 uses Collaborative Data Objects or CDO to talk to the Exchange 5.5 server, the same mechanism as Outlook Web Access for Exchange 5.5.

Additional query words: oma55

Keywords: kbbug kbnofix KB297976

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