.reg

What is a .reg file?

REG files import or export Windows registry settings — text files that can modify system configuration with a double-click.

Use caution
Type System
By Microsoft
MIME text/x-ms-regedit

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What is it

A .reg file is a plain text script that adds, modifies, or deletes entries in the Windows Registry — the central database of system and application settings. Double-clicking a .reg file prompts to merge it into the registry. This makes reg files powerful but dangerous: a malicious .reg file can disable security features, change system behaviour, or prepare the system for further exploitation.

The format is simple: registry paths in square brackets, followed by value names, types, and data. `Windows Registry Editor Version 5.00` is the required header. Registry Editor (`regedit.exe`) can export settings as .reg files for backup or sharing. System administrators use .reg files for deploying consistent settings across machines.

Never double-click a .reg file from an untrusted source. Always open it in a text editor first to review the changes. Look for suspicious entries modifying security settings, startup programs, or firewall rules. The Windows Registry is powerful but fragile — incorrect modifications can prevent Windows from booting.

Technical details
Full Name
Windows Registry File
MIME Type
text/x-ms-regedit
Developer
Microsoft
Magic Bytes
N/A
Safety
.reg requires caution. REG files modify Windows system settings. Never run .reg files from untrusted sources. Always review contents in a text editor before importing.
What opens it
Any text editor (to review)
FREE Windows
Registry Editor (regedit)
FREE Windows
FAQ
Is it safe to run a .reg file?
Only if you trust the source and have reviewed the contents. Open .reg files in Notepad first to see exactly what registry changes will be made. Malicious .reg files can compromise system security.
How do I back up registry settings?
In Registry Editor (regedit), right-click a key and select Export. This creates a .reg file that can be imported later to restore those settings. Always back up before making registry changes.
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