What Is the Windows Registry?

Windows Registry: What it is & what it's used for

The Windows Registry is a collection of databases of configuration settings for Microsoft Windows operating systems.

What Is the Windows Registry Used For?

Screenshot of the registry hives in the Windows 10 Registry Editor
Registry Hives (Windows 10).

The Windows Registry stores much of the information and settings for software programs, hardware devices, user preferences, and operating-system configurations.

For example, when a new program is installed, a new set of instructions and file references may be added to the registry in a specific location for the program, and others that may interact with it, to refer to for more information like where the files are located, which options to use in the program, etc.

In many ways, the registry can be thought of as a kind of DNA for the Windows operating system.

It's not necessary for all Windows applications to use the Windows Registry. Some programs store their configurations in XML or other types of files instead of the registry, and others are entirely portable and store their data in an executable file.

How to Access the Windows Registry

The Windows Registry is accessed and configured using the Registry Editor program, a free registry editing utility included by default with every version of Microsoft Windows going back to Windows 95.

Registry Editor isn't a program you download. Instead, it can be accessed by executing regedit from the Command Prompt or from the search or Run box from the Start menu. See How to Open Registry Editor if you need help.

Registry Editor is the face of the registry and is the way to view and make changes to the registry, but it's not the registry itself. Technically, the registry is the collective name for various database files located in the Windows installation directory.

How to Use the Windows Registry

The registry contains registry values (which are instructions), located within registry keys (folders that contain more data), all within one of several registry hives (folders that categorize all the data in the registry using subfolders). Making changes to these values and keys using Registry Editor change the configuration that a particular value controls.

See How to Add, Change, & Delete Registry Keys & Values for lots of help on the best ways to make edits to the Windows Registry.

Making changes to registry values solves a problem, answers a question, or alters a program in some way:

The registry is constantly referenced by Windows and other programs. When you make changes to nearly any setting, changes are also made to the appropriate areas in the registry, though these changes are sometimes not realized until you reboot the computer.

Considering how important the Windows Registry is, backing up the parts of it you're changing, before you change them, is very important. Windows Registry backup files are saved as REG files.

See How to Back up the Windows Registry for help generating manual backups. Additionally, just in case you need it, here's our How to Restore the Windows Registry tutorial, which explains how to import REG files back into the Registry Editor.

Windows Registry Availability

The Windows Registry and the Microsoft Registry Editor program are available in nearly every Microsoft Windows version including Windows 10Windows 8Windows 7Windows VistaWindows XP, Windows 2000, Windows NT, Windows 98, and Windows 95.

Even though the registry is available in almost every Windows version, some very small differences do exist between them.

The Windows Registry has replaced autoexec.bat, config.sys, and nearly all of the INI files that contained configuration information in MS-DOS and in very early versions of Windows.

Where Is the Windows Registry Stored?

The SAM, SECURITY, SOFTWARE, SYSTEM, and DEFAULT registry files, among others, are stored in newer versions of Windows (Windows XP through Windows 10) in the %SystemRoot%\System32\Config\ folder. 

Older versions of Windows use the %WINDIR% folder to store registry data as DAT files. Windows 3.11 uses only one registry file for the entire Windows Registry, called REG.DAT.

Windows 2000 keeps a backup copy of the HKEY_LOCAL_MACHINE System key that it uses to troubleshoot a problem with the existing one.