DMG Converter > Convert DMG Disk Image to 7Z / RAR / TAR / TAR.BZ2 / TAR.GZ / ZIP

What does DMG Converter do?

DMG is a disk image; it appears as a disk when “mounted” in Finder. Under the format, there can be variants like UDIF/NDIF, as well as optional compression/encryption layers.

Therefore, you must divide “DMG conversion” into two clear modes:

Mode 1 > Content Mode (recommended, most users want this)

Purpose: Extract files/folders from the DMG > repackage in the target archive format.

Flow:

1. DMG is analyzed (partition/volume list)
2. Selected volume is read (HFS+/APFS, etc.)
3. Files are extracted
4. Archived in the target format (ZIP/7Z/RAR/TAR/TAR.GZ/TAR.BZ2)

This mode is the right answer for users who say “I want the files”.

Mode 2 > Image Preservation Mode (for technical users)

Purpose: Preserve the “disk image” character of the DMG > keep the image in raw form instead of extracting the content file by file.

Flow options:

• In macOS environment: convert/output generation with hdiutil (e.g., convert)
• In Linux environment: obtain raw image with dmg2img

Then according to user choice:

• The output is placed as a “image file” in a single file ZIP/7Z/RAR/TAR.GZ (e.g., image.iso or image.img).

This mode is necessary for those who want a “bootable image / exact disk”.

Supported conversions

• DMG to 7Z
• DMG to RAR
• DMG to TAR
• DMG to TAR.BZ2
• DMG to TAR.GZ
• DMG to ZIP

Real-life challenging scenarios encountered in DMG (product quality is revealed here)

• Multiple partitions/volumes: conversion may produce “empty output” without prompting the user to select a volume.
• APFS vs HFS+: some extractors may not read every file system with the same quality; just because 7-Zip lists DMG and APFS in its “unpack” list does not guarantee 100% extraction for every DMG.
• Encrypted DMG: password should be requested; a clear error should return on wrong password. (DMG has encryption layers.)
• Compressed DMG: different compressions may be seen within UDIF; not every combination opens in every tool.

Interface flow (single interface)

1. Upload DMG
2. Analysis screen:

• Volume list (name, size, FS type)
• “Is it encrypted / compressed” warning
• Mode selection: Content Mode / Image Preservation Mode

3. Select target format
4. Settings:

• volume selection
• file name standard
• metadata behavior (permissions, symlink)
• compression level

5. Convert
6. Download single file

Settings (detail)

• Volume selection: “Default volume” + dropdown list
• File/metadata
  • “Preserve folder structure” (default on)
  • symlink behavior: preserve / convert to file (especially for Windows compatibility)
• Compression level: fast / balanced / maximum
• Image Preservation Mode output:
  • “Produce ISO” (hdiutil convert flow in macOS)
  • “Produce IMG” (dmg2img flow in Linux)

Error messages (short, but clear)

• “DMG could not be read > file is corrupted or unsupported DMG type.”
• “Password required > this DMG is encrypted.”
• “Selected volume could not be read > file system is not supported.”
• “RAR output is not supported > select ZIP or 7Z.”

Use cases

• Extracting files from a macOS application DMG and sharing them as ZIP with the Windows team
• Packaging DMG content as Linux tarball standard (tar.gz)
• Forensics/ops team for “preserving the image” > keeping the image in raw form and transporting it in a single package

FAQs

• Is DMG like a ZIP? No; it is a disk image, it has the logic of a mounted volume.
• Can DMG be worked with from the command line in macOS? Yes, there are verbs like hdiutil attach/convert/verify.