This article was previously published under Q329034
When you run the Disk Defragmenter (Dfrg.msc) utility, and then you close the Disk Defragmenter window, your computer may crash.
This problem is caused by the FC42.DLL!AfxCallWndProc method and by the MFC42U.DLL!CFrameWnd::OnActivateTopLevel method.
A supported hotfix 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 hotfix may receive additional testing. Therefore, if you are not severely affected by this problem, we recommend that you wait for the next service pack that contains this hotfix.
To resolve this problem immediately, contact Microsoft Product Support Services to obtain the hotfix. For a complete list of Microsoft Product Support Services telephone 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.
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.