.reg File — Windows Registry File

REG files are Windows Registry script files that contain registry keys and values in a human-readable text format. When executed (double-clicked), REG files merge their contents into the Windows Registry — the hierarchical database that stores operating system configuration, user preferences, software settings, and hardware information. REG files start with a version header (Windows Registry Editor Version 5.00) followed by registry key paths in square brackets and name-value pairs below each key. The format supports string values (REG_SZ), expanded strings (REG_EXPAND_SZ), multi-string values (REG_MULTI_SZ), DWORD integers (REG_DWORD), QWORD integers (REG_QWORD), and binary data (REG_BINARY). Key paths prefixed with a minus sign (-) indicate deletion of that key. REG files are used for distributing registry tweaks, backing up and restoring registry settings, deploying configuration changes across multiple computers, and sharing system customizations. They can be exported from the Registry Editor (regedit.exe) and imported through regedit or the reg command-line tool. Caution is essential when applying REG files, as incorrect registry modifications can cause system instability or prevent Windows from booting.