DOCUMENT:Q235496 11-JUN-2002 [winnt] TITLE :Enabling a Memory.dmp File Capture Using the GUI or the Registry PRODUCT :Microsoft Windows NT PROD/VER:winnt:3.5,3.51,4.0 OPER/SYS: KEYWORDS:kbenv ====================================================================== ------------------------------------------------------------------------------- The information in this article applies to: - Microsoft Windows NT Server versions 3.5, 3.51, 4.0 - Microsoft Windows NT Workstation versions 3.5, 3.51, 4.0 ------------------------------------------------------------------------------- IMPORTANT: This article contains information about modifying the registry. Before you modify the registry, make sure to back it up and make sure that you understand how to restore the registry if a problem occurs. For information about how to back up, restore, and edit the registry, click the following article number to view the article in the Microsoft Knowledge Base: Q256986 Description of the Microsoft Windows Registry SUMMARY ======= This article describes how to enable a Memory.dmp file capture using the graphical user interface (GUI) of Windows NT or by making changes to the registry. MORE INFORMATION ================ To enable Windows NT to capture a Memory.dmp file, you must be able to gain access to the GUI or the registry file. Use the appropriate method to enable Windows NT to capture a Memory.dmp file. Method 1: Enabling a Memory.dmp File Capture Using the GUI ---------------------------------------------------------- 1. Click Start, point to Settings, click Control Panel, and then double-click System. 2. On the Startup/Shutdown tab in the Recovery section, you can choose from the following options: - Write an event to the system log This option is enabled by default in Windows NT Server 4.0 Service Pack 4 or later. If the computer stops responding, an event is written to the system log, which you can view using Event Viewer. For example: Event ID: 1001 Source: Save Dump Description: The computer has rebooted from a bugcheck. The bugcheck was: 0xc000021a (0xe1270188, 0x00000001, 0x00000000, 0x00000000). Microsoft Windows NT (v15.1381). A dump was saved in: C:\Winnt\Memory.dmp. - Send an administrative alert This option performs a net send command and sends an alert over the network to the administrator. - Write debugging information to This option enables the capture of a dump file. It also specifies the location to store the dump file (the default location is the %SystemRoot%\Memory.dmp folder). NOTE: Although you can redirect the Memory.dmp file to another drive or partition, you must have sufficient space on the partition. When a save dump operation is performed, the contents of kernel mode address space are temporarily stored in the page file on the system partition and are then moved to the alternate location when the computer is restarted. For Windows NT to write a memory dump, the paging file on the system drive must be large enough to hold all of physical RAM plus 1 megabyte (MB). - Overwrite an existing file If you choose this option, a new Memory.dmp file overwrites a previous Memory.dmp file (which conserves disk space). - Automatically reboot If you choose this option, the computer is restarted after a bugcheck occurs. Method 2: Enabling a Memory.dmp File Capture Using the Registry --------------------------------------------------------------- WARNING: If you use Registry Editor incorrectly, you may cause serious problems that may require you to reinstall your operating system. Microsoft cannot guarantee that you can solve problems that result from using Registry Editor incorrectly. Use Registry Editor at your own risk. You may encounter situations when you cannot gain access to the GUI of Windows NT. Use the appropriate method to capture a Memory.dmp file using the registry. For Computers Using the FAT File System: 1. Boot from an MS-DOS disk. 2. Locate the %SystemRoot%\System32\Config folder (%SystemRoot% is the name of the folder in which you installed Windows NT). 3. Locate the System file (without any extension) and copy it to a disk. 4. Insert the disk into the drive of another Windows NT-based computer, and then start Registry Editor (Regedt32.exe). 5. Ensure the HKEY_LOCAL_MACHINE hive is selected. 6. On the Registry menu, click Load Hive. 7. Locate the System file, and then click Open. 8. The Load Hive dialog box appears. In the Key Name box, type a temporary name (for example, "test" (without the quotation marks)), and then click OK. 9. A key named Test appears. This is a copy of your System hive from the other Windows NT-based computer. 10. Locate the following registry key: HKEY_LOCAL_MACHINE\TEST\ControlSet001\Control\Crash Control 11. On the right-hand side of the screen, the following values that correspond to the GUI interface are displayed: Value Name: AutoReboot Data Type: REG_DWORD Data: 0|1 (Disabled|Enabled) Value Name: CrashDumpEnabled Data Type: REG_DWORD Data: 0|1 (Disabled|Enabled) Value Name: DumpFile Data Type: REG_EXPAND_SZ Data: %SystemRoot%\Memory.dmp (location to save the dump file) Value Name: LogEvent Data Type: REG_DWORD Data: 0|1 (Disabled|Enabled) Logs an event to the System log when a crash occurs Value Name: Overwrite Data Type: REG_DWORD Data: 0|1 (Disabled|Enabled) Overwrites an existing dump file Value Name: SendAlert Data Type: REG_DWORD Data: (Disabled|Enabled) Sends an administrative alert 12. After you make the appropriate changes, copy the updated System file back to the %SystemRoot%\System32\Config folder on the original computer. For Computers Using the NTFS File System: Because of the security features in the file system, you cannot simply copy the file, make changes, and then copy the file back to the computer. To gain access to the file system, you must perform a parallel installation of Windows NT. A parallel installation puts another copy of the operating system in another folder, which allows you to gain access to the file system. After the parallel installation is finished, use the following steps: 1. Start Registry Editor (Regedt32.exe). 2. Ensure the HKEY_LOCAL_MACHINE hive is selected. 3. On the Registry menu, click Load Hive. 4. Locate the %SystemRoot%\System32\Config folder on the original installation of Windows NT, click the System file, and then click Open. 5. The Load Hive dialog box appears. In the Key Name box, type an appropriate temporary name (for example, "test" (without the quotation marks)). A key named Test appears. This is the System hive from the other installation of Windows NT. 6. Locate the following registry key: HKEY_LOCAL_MACHINE\TEST\ControlSet001\Control\Crash Control 7. On the right-hand side of the page, the values that correspond to the GUI interface are displayed. Make and save the appropriate changes. 8. Restart your original installation of Windows NT. For Remote Computers: 1. Start Registry Editor (Regedt32.exe). 2. On the Registry menu, click Select Computer, and then type the name of the remote computer. 3. Locate the following registry key: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\CrashControl 4. On the right-hand side of the page, the values that correspond to the GUI interface are displayed. Make and save the appropriate changes. 5. Quit Registry Editor, and then restart the computer. REFERENCES ========== For additional information, please click the article numbers below to view the articles in the Microsoft Knowledge Base: Q130536 Windows NT Does Not Save Memory Dump File After a Crash Q141468 Additional Pagefile Created Setting Up Memory Dump Q174630 Windows NT Restarts Continuously with Blue Screen Q244139 Windows 2000 Feature Allows a Memory.dmp File to Be Generated [ntrelease] Additional query words: ====================================================================== Keywords : kbenv Technology : kbWinNTsearch kbWinNTWsearch kbWinNTW400 kbWinNTW400search kbWinNT351search kbWinNT350search kbWinNT400search kbWinNTW350 kbWinNTW350search kbWinNTW351search kbWinNTW351 kbWinNTSsearch kbWinNTS400search kbWinNTS400 kbWinNTS351 kbWinNTS350 kbWinNTS351search kbWinNTS350search Version : winnt:3.5,3.51,4.0 Issue type : kbinfo ============================================================================= THE INFORMATION PROVIDED IN THE MICROSOFT KNOWLEDGE BASE IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND. MICROSOFT DISCLAIMS ALL WARRANTIES, EITHER EXPRESS OR IMPLIED, INCLUDING THE WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT SHALL MICROSOFT CORPORATION OR ITS SUPPLIERS BE LIABLE FOR ANY DAMAGES WHATSOEVER INCLUDING DIRECT, INDIRECT, INCIDENTAL, CONSEQUENTIAL, LOSS OF BUSINESS PROFITS OR SPECIAL DAMAGES, EVEN IF MICROSOFT CORPORATION OR ITS SUPPLIERS HAVE BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES. SOME STATES DO NOT ALLOW THE EXCLUSION OR LIMITATION OF LIABILITY FOR CONSEQUENTIAL OR INCIDENTAL DAMAGES SO THE FOREGOING LIMITATION MAY NOT APPLY. Copyright Microsoft Corporation 2002.