Stop 0xC000021A When Starting Task Manager with CTRL+ALT+DEL

ID: Q183840

The information in this article applies to:

Microsoft Windows NT Server version 4.0
Microsoft Windows NT Workstation version 4.0
Microsoft Windows NT Server version 4.0, Terminal Server Edition

SYMPTOMS

The Task Manager can be started by pressing CTRL+ALT+DEL and then clicking Task Manager on the Security dialog box. However, if there are many user environment variables defined, running Task Manager from the Security dialog box may cause a STOP C000021A exception error message.

CAUSE

The System Environment Block becomes corrupted by the Winlogon service if the size of the User Environment is significantly large. This can also be caused by the installation of many applications on a system.

RESOLUTION

To resolve this problem, obtain the latest service pack for Windows NT 4.0 or Windows NT Server 4.0, Terminal Server Edition. For additional information, please see the following article in the Microsoft Knowledge Base:

Q152734 How to Obtain the Latest Windows NT 4.0 Service Pack

STATUS

Microsoft has confirmed this to be a problem in Windows NT 4.0 and Windows NT Server 4.0, Terminal Server Edition. This problem was first corrected in Windows NT 4.0 Service Pack 4.0 and Windows NT Server 4.0, Terminal Server Edition Service Pack 4.

Additional query words: environment winlogon crash hang

Keywords : NT4SP4Fix ntstop kbbug4.00 kbfix4.00.sp4 NTSrvWkst
Version : WinNT:4.0
Platform : winnt
Issue type : kbbug