How To Backup, Edit, and Restore the Registry in Windows NT 4.0

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.

How to Back Up the Registry

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. Or, 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: 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.

How to Edit the Registry

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.

How to Restore the Registry

How to Restore Registry Keys

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.

How to Restore the Whole Registry

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.