Application Using SetOwner May Hang Windows NT User Interface

• Microsoft Windows NT Server version 4.0
• Microsoft Windows NT Workstation version 4.0

SYMPTOMS

An application runs under Windows NT and the computer appears to stop responding (hang). The user interface is frozen and it does not respond to mouse and keyboard input.

The computer can still be accessed from the network, but you are unable to start services that require a new process to be started.

CAUSE

The application used the Win32 API SetOwner and defined window_1 to be owned by window_2, but also window_2 to be owned by window_1. When looking for the top-level window of the hierarchy (the one without an owner), the Win32 subsystem runs into an endless loop.

The ownership relations created by the applications will render the application unusable for the operating system, but must not cause the User Interface to hang.

RESOLUTION

To resolve this problem, obtain the following fix or wait for the next Windows NT service pack.

This fix should have the following time stamp:

   10/21/97  06:06p               323,344 user32.dll (Intel)
   11/07/97  04:15p             1,235,440 win32k.sys (Intel)

   10/21/97  07:00p               579,344 user32.dll (Alpha)
   11/07/97  05:12p             2,047,120 win32k.sys  (Alpha)

STATUS

Microsoft has confirmed this to be a problem in Windows NT version 4.0. A supported fix is now available, but has not been fully regression tested and should be applied only to systems experiencing this specific problem. Unless you are severely impacted by this specific problem, Microsoft recommends that you wait for the next Service Pack that contains this fix. Contact Microsoft Technical Support for more information.

Keywords          : kbbug4.00 kbfix4.00 nt32ap NTSrvWkst
Version           : WinNT:4.0
Platform          : winnt
Issue type        : kbbug
Solution Type     : kbfix