.REG file signature
A Windows Registry text file begins with the bytes 72 65 67 66 (regf in ASCII) at the start of the file. The signature is the same whatever the file is named, which is why a renamed or extensionless WINREGISTRY file is still recognisable.
Signature
| Offset | Hex | ASCII |
|---|---|---|
| 0 | 72 65 67 66 | regf |
MIME type: text/plain · usual extensions: .reg
How to check a file's signature
Without installing anything: drop the file on our detector. It reads the bytes in your browser and shows the hex dump alongside the verdict; nothing is uploaded.
macOS and Linux (Terminal):
xxd -l 32 file.reg
file file.regWindows (PowerShell):
Format-Hex -Path file.reg -Count 32If the bytes do not match
A file named .reg whose first bytes are something else is not a WINREGISTRY file. The common explanations are a wrong or deliberately misleading extension, a download that saved an HTML error page instead of the file, or a container such as ZIP wrapping the real content. The detector reports what the bytes say; the WINREGISTRY guide explains what a genuine file should contain.