---
title: ".reg file — what it is and how to open it"
description: "A .reg file is a Windows Registry File. A text file that writes settings into the Windows registry when you double-click it. How to open one on Windows, macOS and Linux, and what to convert it to."
url: https://atoneplace.net/file/reg/
site: "At One Place"
---

# .reg files

**.reg file: Windows Registry File**

A text file that writes settings into the Windows registry when you double-click it.

## What opens a .reg file

- **Windows:** Notepad (built in — right-click > Edit to read it safely), Registry Editor (built in — merges it)
- **macOS:** Any text editor (to read — no effect on macOS)
- **Linux:** Any text editor (to read — no effect on Linux)

## What a .reg file is

A .reg file lists registry keys and values, and double-clicking it merges them into your registry after one confirmation prompt — it changes system configuration immediately. Always right-click and choose Edit to read it in Notepad first, because a malicious or wrong .reg can break Windows. Registry Editor exports the same format, which is the sensible way to back up a key before changing it.

## Converting it

A .reg file is commonly converted to .txt. It is a plain text format, so any text editor can open and edit it directly.

## Details

- **Extension:** .reg
- **Full name:** Windows Registry File
- **Category:** Data
- **MIME type:** text/plain
- **Created by:** Microsoft
- **Format:** Plain text

## Common questions

### How do I open a .reg file?

On Windows use Notepad (built in — right-click > Edit to read it safely); on macOS use Any text editor (to read — no effect on macOS); on Linux use Any text editor (to read — no effect on Linux). A text file that writes settings into the Windows registry when you double-click it.

### What is a .reg file?

Windows Registry File. A .reg file lists registry keys and values, and double-clicking it merges them into your registry after one confirmation prompt — it changes system configuration immediately. Always right-click and choose Edit to read it in Notepad first, because a malicious or wrong .reg can break Windows.

### Can I convert a .reg file?

Yes. It is usually converted to .txt, either by exporting from one of the programs listed above or with a format converter.

## Related pages

- [.csv — Comma-Separated Values](https://atoneplace.net/file/csv/)
- [.json — JavaScript Object Notation](https://atoneplace.net/file/json/)
- [.xml — Extensible Markup Language](https://atoneplace.net/file/xml/)
- [.yaml — YAML Data File](https://atoneplace.net/file/yaml/)
- [.log — Log File](https://atoneplace.net/file/log/)
- [.torrent — BitTorrent Metainfo File](https://atoneplace.net/file/torrent/)
- [.dat — Generic Data File](https://atoneplace.net/file/dat/)
- [.vcf — vCard Contact File](https://atoneplace.net/file/vcf/)
- [.sql — SQL Script](https://atoneplace.net/file/sql/)
- [.ics — iCalendar Event](https://atoneplace.net/file/ics/)
- [.sqlite — SQLite Database](https://atoneplace.net/file/sqlite/)
- [.db — Generic Database File](https://atoneplace.net/file/db/)

## Sources

- Media Types Registry — IANA (https://www.iana.org/assignments/media-types/)
- Official vendor product documentation — At One Place (/about/)