Windows 2000 Stop Messages
This Stop message occurs when a user-mode subsystem, such as Winlogon or the Client/Server Runtime Subsystem (CSRSS), is fatally compromised and security can no longer be guaranteed. The operating system switches into kernel-mode and generates this error. Because Windows 2000 cannot run without Winlogon or CSRSS, this is one of the few situations where the failure of a user-mode service can bring down the system. Running the kernel debugger is not useful in this situation because the actual error occurred in a user-mode process.
Interpreting the Message
The first three parameters listed in the message are defined in order of appearance as follows:
Status code
0 (zero)
0 (zero)
For information about all possible status codes that might be returned, see the file Ntstatus.h of the Windows 2000 Device Driver Development Kit ** (DDK). For information about the DDK, see Additional Resources at the end of this chapter.
Resolving the Problem
Device drivers, system services, and third-party applications. Because Stop 0xC000021A occurs in a user-mode process, the most common culprits are third-party applications. If the error occurred after the installation of a new or updated device driver, system service, or third-party application, the new software needs to be removed or disabled. Contact the manufacturer of the software about a possible update.
If the error occurs during system startup, restart your computer, and press F8 at the character-mode screen that displays the prompt For troubleshooting and advanced startup options for Windows 2000, press F8. On the resulting Windows 2000 Advanced Options menu, choose the Last Known Good Configuration option. This option is most effective when only one driver or service is added at a time. If this does not resolve the error, try manually removing the offending software by restarting the computer in Safe Mode and renaming or uninstalling the faulty software. If the faulty software is used as part of the system startup process in Safe Mode, you need to start the computer using the Recovery Console in order to access the file. For more information about Safe Mode and the Recovery Console, see Troubleshooting Tools and Strategies in this book. If a newly installed piece if hardware is suspected, remove it to see if this resolves the issue.
Try running the Emergency Recovery Disk (ERD) and allow the system to repair any errors that it detects. For more information about the ERD, see Troubleshooting Tools and Strategies in this book.
Mismatched system files. Mismatched system files can also cause this error. If you can successfully start the computer using Safe Mode, try using the System File Checker (SFC) to correct the problem. Open up the Run dialog box, type sfc /scannow , and then press ENTER. For more information about System File Checker and Safe Mode, see Troubleshooting Tools and Strategies in this book. If SFC does not correct the problem, running a full system restore from tape might generate this error (some restore programs might skip restoring system files they determine are in use). Check to see if there is an updated version of the Backup/Restore program available from the manufacturer.
Microsoft periodically releases a package of product improvements and problem resolutions for Windows 2000 called a Service Pack. Because many problems are resolved by installing the latest Service Pack, it is recommended that all users install them as they become available. To check which Service Pack, if any, is installed on your system, click Start , click Run , type winver, and then press ENTER. The About Windows 2000 dialog box displays the Windows version number and the version number of the Service Pack, if one has been installed.
Occasionally, remedies to specific problems are developed after the release of a Service Pack. These remedies are called hotfixes. Microsoft does not recommend that you install a post–Service Pack hotfix unless the specific problem it addresses has been encountered. Service Packs include all of the hotfixes released since the release of the previous Service Pack. The status of hotfix installations is not indicated in the About Windows 2000 dialog box. For more information about Service Packs and hotfixes, see Additional Resources at the end of this chapter.
For more troubleshooting information about the 0xC000021A Stop message, refer to the Microsoft Knowledge Base link, using the keywords winnt and 0xC000021A . For information about this resource, see Additional Resources at the end of this chapter.