Applies To:
  • CitectSCADA 6.00
  • CitectHMI 6.00

Microsoft have advised that Registry handle leaks occur in applications that use MSXML DOM or XML classes after installing Microsoft office 2003. 

The following Microsoft Knowledge Base article explains the problem and a workaround.
Citect has confirmed this to be a problem in CitectHMI/SCADA version 6.00 Web Client but the leak is not significant. We will post new information here as it becomes available.

Microsoft Knowledge Base article 841532:
Registry handle leaks occur in applications that use MSXML DOM or XML classes after you install Microsoft Office 2003
View products that this article applies to.
Article ID : 841532
Last Review : July 15, 2004
Revision : 1.0

Applications that use the Microsoft XML Parser (MSXML) Document Object Model (DOM) or the XML classes in the Microsoft .NET Framework experience a slow and steady increase in handle usage when the applications are opening XML files from XML Web services. This problem may exhaust process resources and cause an error or an out-of-memory condition. The program must be restarted to reclaim the lost handles. This problem occurs on computers that have Microsoft Office 2003 installed. The problem does not occur on computers that have earlier versions of Microsoft Office installed.
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This problem is caused by a leak of registry key handles in a client-side MIME protocol filter for XML files that are returned from XML Web services. The Microsoft Office XML MIME filter (Msoxmlmf.dll) is a registered MIME protocol handler. Msoxmlmf.dll can load indirectly in any application that uses the MSXML to parse XML data from an XML Web service. The filter is used by the Wininet library component and the Urlmon library component to identify XML files that are associated with Office 2003. One registry key handle is leaked every time that the filter object is created. The filter object is typically created one time per session. However, services that destroy and re-create repeated XMLHttpRequest objects and that parse the resulting XML may experience conditions that cause a new session to be created for every request. When a new session is created for every request, a slow leak of registry key handles occurs.
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Clients can remove the filter to avoid the leak if the problem is so serious that it causes application errors in other processes. To remove the filter, follow these steps:1. Verify that the Msoxmlmf.dll filter is installed in the Office shared folder. The following is the default location for this folder:
C:\Program Files\Common Files\Microsoft Shared\Office11\Msoxmlmf.dll
2. Click Start, click Run, type regsvr32.exe /u "c:\program files\common files\microsoft shared\office11\msoxmlmf.dll", and then click OK.

If the Msoxmlmf.dll filter is installed in a location that is not the default location, type the path of the actual location of the filter.

Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.

The Microsoft Office XML MIME Filter (Msoxmlmf.dll) is registered under the following registry key:
Removing this key also prevents the filter from loading in a custom application.