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What is the .REG File Extension?

.REG File Extension Description:

Files with the .reg file extension are system files used to update the Windows Registry when activated. There are custom files with the .reg file extension that can be created to serve the purpose of altering different aspects of Windows. By definition, the Windows Registry is the directory wherein the settings and options for the operating system for Microsoft Windows 32-bit versions and Windows Mobile 64-bit versions are stored. In addition, the Windows Registry contains settings and information for all the operating system's software, hardware, users, preferences, and on most of the non-operating system software.

Files with the .reg file extension are also known as Registration entries. Such entries are text-based files that are easily readable by humans and are used for storing portions of the registry. Later NT-based operating systems and Windows 2000 files with the .reg file extension are Unicode-based and contain the "Windows Registry Editor Version 5.00" string at the beginning. On NT 4.0 and Windows 9x systems, the files with the .reg file extension contain the "REGEDIT4" string and are ANSI-based.

The Regedit.exe file also uses the files with the .reg file extension to import and export registry values and subkeys. The user can also utilize the files with the .reg file format to remotely allocate registry changes to several Windows-based machines. When the user runs a file with the .reg file extension, the contents of such file will merge into the local registry.

The files with the .reg file extension have the following syntax:


Blank line




Blank line



The first line of the syntax, which is RegistryEditorVersion, is either the "REGEDIT4" for Windows NT 4.0 and Windows 98, or the "Windows Registry Editor Version 5.00" for Windows Server 2003, Windows XP and Windows 2000.

The Blank line identifies the beginning of a new registry path. Each subkey or key is considered as a new registry path. In case the user has several keys in his or her file with the .reg file format, the blank lines can aid him or her in examining and troubleshooting the contents.

The RegistryPathx is the subkey path that holds the first value the user is importing. An example of a path is the "[HKEY_LOCAL_MACHINE/ SOFTWARE/ Policies/ Microsoft/ Windows/ System]". A file with the .reg file format can have several registry paths. The contents of the registry files are also sent to the registry in a user-defined order. Therefore, if the user wants to make a new subkey with another subkey underneath, he or she must enter the lines in the correct order.

Lastly, the DataItemNamex is the name of the data the user wants to import. On the other hand, the DataTypex is the type of data for the registry value, which immediately follows the equal sign.

Author: Microsoft
Author URL:
Related Applications: Windows Registry
Common Path: N/A


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Do you have errors with .REG files?

The Usual Cause of .REG files Errors to Occur:

When you receive errors with .REG files you are likely receiving a severe Windows file error - the error could be the result of corruption in your registry and you should work to correct it at once to avert further damage to the registry. As long as the errors persist your system stays capable of potential blue screen errors, system failure and fatal crashes.

Symptoms of .REG files Errors:

.REG files errors bring forth numerous symptoms, including: personal computer hangs while starting up or shutting down, softwares lock up, diminished system performance, built-in speaker beeping, trouble loading files, slow system behaviour and problems while installing applications.

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How to Fix .REG File Extension Errors    |    What is the .REG File Extension?    |    Scan for .REG File Extension Errors