IMPORTANT: This 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.

• How to Back Up the Registry
• How to Export Registry Keys
• How to Back Up the Whole Registry
• How to Edit the Registry
• How to Restore Registry Keys
• How to Restore the Whole Registry

This step-by-step article describes how to back up, edit, and restore the registry in Windows NT 4.0. Microsoft recommends that before you edit the registry, you back up the registry and understand how to restore it if a problem occurs.

Before you edit the registry, export the keys in the registry that you plan to edit, or back up the whole registry. If a problem occurs, you can then follow the steps in the How to Restore the Registry section of this article to restore the registry to its previous state.

How to Export Registry Keys

You can follow these steps to export a registry key before you edit it. NOTE: Do not follow these steps to export a whole registry hive (for example, the HKEY_CURRENT_USER hive). If you must back up whole registry hives, back up the whole registry instead.

1. Click Start, and then click Run.
2. In the Open box, type regedt32, and then click OK.
3. Locate and then click the key that contains the values that you plan to edit.
4. On the Registry menu, click Save Key.
5. In the Save in box, select a location in which to save the .reg file, type a file name in the File name box, and then click Save.

How to Back Up the Whole Registry

To back up the whole registry, use the Windows NT Backup tool (Ntbackup.exe) and use the option to back up the registry. Alternatively, run the rdisk /s command. For additional information about using the Rdisk tool to update your repair information, click the article number below to view the article in the Microsoft Knowledge Base: 156328 Description of Windows NT Emergency Repair Disk

NOTE: You must have a supported tape drive to use Windows NT Backup to back up the registry. If you do not have a supported tape drive, use Rdisk. When you run the rdisk /s command to update your repair information, compressed copies of the registry files are placed in the %SystemRoot%\Repair folder. If you cannot start Windows NT after you edit the registry, you can manually replace the registry files by expanding the copies in the %SystemRoot%\Repair folder.

To edit the registry, Microsoft recommends that you follow the steps in the Microsoft documentation only. If possible, use the Windows user interface instead of directly editing the registry.

Using Registry Editor incorrectly can cause serious problems that may require that you reinstall your operating system. Microsoft cannot guarantee that problems that result from incorrectly using Registry Editor can be solved. Use Registry Editor at your own risk.

For more information about editing the registry, follow these steps in Registry Editor (Regedt32.exe):

1. On the Help menu, click Contents.
2. Click the Contents tab.
3. Double-click the topic that you want to read.

IMPORTANT: The following 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.

This describes how you can use Regedit.exe to rename a registry key on a remote or local computer when it is loaded with Regedt32.exe.
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.

Local computer

1. Start Registry Editor (Regedit.exe).
2. Click the key to be renamed. On the Edit menu, click Rename, type the new name for the key, and then press ENTER.
3. Quit Registry Editor.

Remote computer

1. Start Registry Editor (Regedit.exe).
2. Click Connect Network Registry on the Registry menu, type the name of the remote computer, and then click OK.
3. Click the key to be renamed. On the Edit menu, click Rename, type the new name for the key, and then press ENTER.
4. After you make the changes to the remote computer's registry, click Disconnect Network Registry on the Registry menu, click the remote computer name, and then click OK.
5. Quit Registry Editor.

1. Click Start, and then click Run.
2. Type regedt32, and then click OK.
3. On the Registry menu, click Restore.
4. Select the .reg file that you saved in the How to Backup the Registry section of this article, and then click Open.
5. Click Yes to continue.

To restore the whole registry, restore a registry backup by using the Windows NT Backup utility.
NOTE: If you ran the rdisk /s command to update the repair information, updated, compressed copies of the registry files are located in the %SystemRoot%\Repair folder. If you cannot start Windows NT after you edit the registry, you can manually replace the registry files in the %SystemRoot%\System32\Config folder by expanding the compressed copies in the %SystemRoot%\Repair folder.
You must start MS-DOS (if the drive uses the FAT file system) or perform a parallel installation of Windows NT (if the drive uses the NTFS file system) to do this. REFERENCES 265422 How RDISK.EXE Updates Repair Information 122857 RDISK /S and RDISK /S- Options in Windows NT

The information in this article applies to:

• Microsoft Windows NT Server 4.0 Terminal Server Edition
• Microsoft Windows NT Server 4.0
• Microsoft Windows NT Server, Enterprise Edition 4.0
• Microsoft Windows NT Workstation 4.0