Error message when you start Outlook 2003: "Cannot start Microsoft Office Outlook. Unable to open the Outlook window. The set of folders could not be opened. Out of memory or system resources"


Consider the following scenario. You configure Microsoft Office Outlook 2003 to connect to a Microsoft Exchange email account. Additionally, you configure the Exchange email account to use Cached Exchange Mode. When you start Outlook, you receive the following error message:

Cannot start Microsoft Office Outlook. Unable to open the Outlook window. The set of folders could not be opened. Out of memory or system resources.


This issue can occur when a new offline folder (.ost) file is created for the same mailbox more than a few hundred times. Every time that a new .ost file is created, data is appended to thePR_PREDECESSOR_CHANGE_LIST property of the Inbox folder. When thePR_PREDECESSOR_CHANGE_LIST property exceeds 8 kilobytes (KB), Outlook displays the error message that is mentioned in the "Symptoms" section.


To work around this problem, use one or more of the following methods:

  • Have the Exchange administrator create a new Exchange mailbox for you. The administrator must also migrate your mailbox data for you.
  • Use Online Mode instead of Cached Exchange Mode. 

More Information

This error does not occur when your Exchange email account is configured in Online Mode. Additionally, this error does not occur when you use Outlook 2007 or Outlook 2010.

To check the size of the PR_PREDECESSOR_CHANGE_LIST property, follow these steps:

1. Download MFCMAPI from

2. Run MFCMAPI.exe.

3. On the Session menu, click Logon.

4. If you are prompted for a profile, select your profile name, and then clickOK.

5. In the top pane, locate the line that corresponds to your mailbox, and then double-click it.

6. In the navigation pane (left-side pane), expand Root Container, and then expand IPM_SUBTREE.

Note If the profile that you chose in step 4 connects to your Exchange mailbox in Online Mode, you should expandTop of Information Store instead of IPM_SUBRTREE.

7. Select Inbox.

8. In the right-side pane, locate PR_PREDECESSOR_CHANGE_LIST, and then double-click it.

9. In the Count of bytes text box, locate the number after the equal sign (=).

If the number is near, equal to, or greater than 8192, Outlook may display the error message that is described in the "Symptoms" section.

Microsoft Internal Support Information

Steps to reproduce.

Product Bug Number:

Office12: 177632
Offbug: 38135

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Article ID: 2502576 - Last Review: Jun 21, 2014 - Revision: 1