Microsoft KB Archive/822472

= The HTTP Virtual Service Resource on an Exchange 2000 Cluster Stops Responding and Delays Occur When Users Access Mailbox Items by Using OWA =

Article ID: 822472

Article Last Modified on 10/26/2006

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APPLIES TO


 * Microsoft Exchange 2000 Enterprise Server

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SYMPTOMS
The HTTP Virtual Service resource on an Exchange 2000 cluster may intermittently stop responding (hang). When this problem occurs, users who access their mailboxes by using Microsoft Outlook Web Access (OWA) may experience long delays when they open messages. Users who access their mailboxes by using a Post Office Protocol version 3 (POP3) client or an Internet Message Access Protocol, Version 4rev1 (IMAP4) client may also experience slow performance.



CAUSE
This problem may occur in environments where the number of mailboxes on the Exchange 2000 cluster is equal to or more than 100,000 and many user account names contain one or more periods.

When an OWA user accesses a mailbox, the Exwin32.dll component creates an e-mail address based on the mailbox that the user wants to access. Typically, the Exwin32.dll component directly queries the Microsoft Active Directory directory service for the mailbox. However, if the user account name contains periods, the Exwin32.dll component may build a mailbox table in memory to search for the user account instead of searching for it in Active Directory. The problem that is described in the &quot;Symptoms&quot; section of this article occurs when multiple threads are backed up as the mailbox tables are created.



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

http://support.microsoft.com/default.aspx?scid=fh;EN-US;CNTACTMS

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.

Component: Exwin32.dll

The English version of this fix 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

21-May-2003 19:19  6.0.6466.0  167,936  Exwin32.dll Note Because of file dependencies, this update requires Exchange 2000 Server Service Pack 3 (SP3). For additional information, click the article number below to view the article in the Microsoft Knowledge Base:

301378 How to Obtain the Latest Exchange 2000 Server Service Pack



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

Keywords: kbqfe kbfix kbexchange2000presp4fix kbbug KB822472

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