You are currently offline, waiting for your internet to reconnect

XADM: Collaborative Data Objects Heap Corruption Occurs When You Try to Access an Exchange Mailbox

Support for Office 2003 has ended

Microsoft ended support for Office 2003 on April 8, 2014. This change has affected your software updates and security options. Learn what this means for you and how to stay protected.

This article has been archived. It is offered "as is" and will no longer be updated.
For a Microsoft Exchange Server 2003 version of this article, see 823343.
For a Microsoft Exchange Server 5.5 version of this article, see 818709.
When you use a third-party program that uses Collaborative Data Objects (CDO) to access a mailbox that is on a computer that is running Microsoft Exchange Server 2000, the third-party program may stop responding.
This problem occurs when you try to access a user account that was previously accessed by a client computer that is running Microsoft Office Outlook 2003.

Outlook 2003 adds a fourth entry to PR_FREEBUSY_ENTRYIDS, a MAPI property with multiple values that is stored in the Inbox folder. The Collaborative Data Objects (CDO) only expect three entries. This causes heap corruption that causes the third-party program to stop responding.

Cumulative Rollup Information

To resolve this problem, obtain the September 2003 Exchange 2000 Server Post-Service Pack 3 (SP3) Rollup. For additional information, click the following article number to view the article in the Microsoft Knowledge Base:
824282 September 2003 Exchange 2000 Server Post-Service Pack 3 Rollup

Hotfix Information

A supported fix is now available from Microsoft, but it is only intended to correct the problem that is described in this article. Only apply it to systems that are experiencing this specific problem. This fix may receive additional testing. Therefore, if you are not severely affected by this problem, Microsoft recommends that you wait for the next Exchange Server 2000 service pack that contains this fix.

To resolve this problem immediately, contact Microsoft Product Support Services to obtain the fix. For a complete list of Microsoft Product Support Services phone numbers and information about support costs, visit the following Microsoft Web site:Note In special cases, charges that are ordinarily incurred for support calls may be canceled if a Microsoft Support Professional determines that a specific update will resolve your problem. The usual support costs will apply to additional support questions and issues that do not qualify for the specific update in question.

You can also download this hotfix from the Microsoft Download Center. To do so, visit the following Microsoft Web site:


There are no prerequisites.

Restart Requirement

You do not have to restart your computer after you apply this hotfix.

Hotfix Replacement Information

This hotfix does not replace any other hotfixes.

File Information

The English version of this hotfix has the file attributes (or later) that are listed in the following table. The dates and times for these files are listed in coordinated universal time (UTC). When you view the file information, it is converted to local time. To find the difference between UTC and local time, use the Time Zone tab in the Date and Time tool in Control Panel.
Date         Time   Version        Size     File name----------------------------------------------------------18-Jul-2003  22:58  6.0.6487.2     716,800  Cdo.dll          15-Jul-2003  20:16  6.0.6487.1     557,056  Cdohtml.dll      
Microsoft has confirmed that this is a problem in the Microsoft products that are listed at the beginning of this article.

Article ID: 824960 - Last Review: 01/07/2015 17:52:05 - Revision: 6.0

Microsoft Exchange 2000 Server Standard Edition, Microsoft Office Outlook 2003

  • kbnosurvey kbarchive kbhotfixserver kbqfe kbexchange2000presp4fix kbfix kbbug KB824960