Open DAT File

Windows Registry DAT Files

Windows registry uses files with DAT extension to store certain parts of the registry. For example, HKEY_CURRENT_USER hive content is stored in NTUSER.DAT file and HKEY_CURRENT_USER hive log is stored in NTUSER.DAT.LOG file.

To work with registry data files Windows has a reg.exe tool shipped in every installation. To use this tool, you need to go to the Start menu and launch “cmd.exe” to start “Command prompt” window. In this window type “REG /?” to see all available options to operate with Windows Registry and data files.

Export registry to DAT file

To export part of the Windows registry to DAT file you need to execute the following command:

reg save HKLM\Software\Test "C:\data\hklm_software_test.dat" /y [/c]

This command will export HKLM\Software\Test registry key contents into hklm_software_test.dat. You can import this file back to the registry using reg load command. Using these commands, you can move part of Windows registry from one computer to another.

Import registry from DAT file

To import part of the registry from DAT file you need to execute the following command:

Reg load HKLM\Software\Test "C:\data\hklm_software_test.dat" /y [/c]

This command will import hklm_software_test.dat into HKLM\Software\Test key. If this key does not exist, it will create it.

Export registry to REG file

“Reg save” command produces DAT file in a registry binary format. Files in this format could only be imported back to the registry. Interpreting information inside them is not possible without knowing exact binary format. In cases when you want to know what exactly is stored in the exported file you should use “reg export” command. This command will export required part of the registry to the REG file which stores information in a human-readable format.

Reg export HKLM\Software\Test C:\data\hklm_software_test.reg

The command above will output HKLM\Software\Test registry key into hklm_software_test.reg in a human readable format. This file could be viewed using notepad or any other text editor. Also you can import this file back into the registry using Reg import command.

Reg import C:\data\hklm_software_test.reg

This command will import hklm_software_test.reg registry data to the same location it was exported from. Note that you cannot specify a different registry location to open data to. To do this you need to use “reg save” and “reg load” commands.