Convert DMG to RAR

A recipient, archive system, or upload service may require RAR instead of Apple’s native disk-image format. The practical conversion extracts the DMG contents and places them in a RAR archive; it does not create an equivalent mountable disk image.

What the DMG format is

DMG is Apple’s disk-image format, used mainly to distribute macOS applications, installers, fonts, system tools, and software updates. macOS opens and mounts DMG files with Finder, Disk Utility, or hdiutil; software vendors create them with hdiutil and other disk-image utilities.

Unlike an ordinary archive, a DMG represents a volume. It can contain HFS+, APFS, or another file system and may include compression, encryption, checksums, permissions, symbolic links, or a bootable layout. Mounting the image is usually safer than treating it as a conventional compressed folder.

What the RAR format is

RAR is a proprietary compressed archive format that bundles files into one archive. It supports solid compression, password protection, encrypted file names, recovery records, and split volumes such as backup.part1.rar and backup.part2.rar.

WinRAR and RARLAB’s command-line tools can create RAR archives. 7-Zip, The Unarchiver, and many other utilities can extract RAR files but generally cannot create them because RAR creation is proprietary.

Convert the DMG contents to RAR

Windows with 7-Zip and WinRAR

1. Install 7-Zip and WinRAR from their official websites.
2. Open the DMG in 7-Zip File Manager and choose Extract, or run 7z x software.dmg -oDMG_contents. Extraction can fail when the image uses an unsupported file system or encryption method.
3. Open the resulting DMG_contents folder in WinRAR, select the files inside it, and choose Add to archive.
4. Set Archive format to RAR, select the required compression level, and click OK. Use Set password and Encrypt file names when the archive must protect both its contents and directory listing.

The second stage can also be run from Command Prompt with winrar a -r output.rar DMG_contents\*. Add a volume size such as -v2g to produce approximately 2 GB parts.

MacOS with hdiutil and RAR

1. Attach the image read-only without opening a Finder window: hdiutil attach -readonly -nobrowse software.dmg.
2. Copy the mounted volume to a normal folder, replacing VolumeName with its actual mounted name: ditto /Volumes/VolumeName DMG_contents.
3. Create the RAR archive with RARLAB’s macOS command-line utility: rar a -r output.rar DMG_contents.
4. Unmount the source image: hdiutil detach /Volumes/VolumeName.

RARLAB’s macOS tool is command-line software rather than a native WinRAR-style graphical application. Keka and The Unarchiver can help extract archives, but they generally do not create RAR files; use an application that invokes the official RAR utility for graphical archive creation.

Online conversion

Services such as Convertio and CloudConvert may offer DMG-to-RAR conversion, but supported formats, size limits, and extraction capabilities can change. Upload only non-sensitive images: the service receives the DMG and may process its contents. Encrypted or unusually large images, uncommon file systems, and DMGs containing macOS applications may fail or produce incomplete results. Local extraction with 7-Zip and WinRAR, or with hdiutil and RAR, avoids those upload and privacy limits.

Compatibility and quality limits

The RAR contains extracted files, not the original disk-image structure. It cannot be mounted as a macOS volume and does not preserve the DMG’s bootable layout, disk-level checksums, or DMG encryption. A password on the DMG does not automatically become a RAR password; configure RAR encryption separately.

Copying a mounted volume with macOS ditto preserves many ordinary macOS attributes, but it may not reproduce every disk-level property. Test applications after extraction when they depend on code signatures, extended attributes, permissions, symbolic links, resource files, or a particular installer layout. If the recipient must mount or install the original image, send the unchanged DMG.

To preserve the original image while using RAR for transport, add the DMG file itself to a RAR archive instead of extracting it. The recipient must first extract the DMG and then mount it; this is packaging a DMG inside RAR, not converting its contents.

DMGs often contain already-compressed files or compressed disk-image data. Maximum RAR compression may therefore reduce the size little while taking longer. Use normal compression for general files and store or low compression when the contents are mainly ZIP, JPEG, MP4, PKG, or other compressed formats.