How to Preview Archives and Disk Images in Finder: Archive Peek for ZIP, DMG, and ISO

Fri, 14 Aug 2026 12:00:00 +0200

This post introduces Archive Peek, my open-source macOS Quick Look extension for looking inside archives, software installers, and disk images directly from Finder.

Press Space Instead of Extracting or Mounting

The idea is simple: select a supported file in Finder, press the Space bar, and browse its contents before deciding what to do with it.

Archive Peek keeps the original file read-only. It does not mount disk images, unpack archives into folders, create temporary raw images, or upload anything. This is useful when you only want to answer a quick question: What is inside this download? Is it the installer I expected? Does this old image contain the file I need?

Figure 1: Archives and ordinary disk images use a familiar Finder-like list.

A Better Preview for Mac Installers

Many DMG and ZIP downloads are not general-purpose archives. They contain one app, package, or macOS dictionary and sometimes a shortcut showing where it should be installed.

Archive Peek recognizes these common installer shapes. Instead of making you search through the full file tree, it presents the app icon, name, version, bundle identifier, minimum macOS version, size, modification date, and installation destination when that information is available.

The same installer view can appear whether the app is inside a DMG, ISO, ZIP, 7Z, or another supported container. The decision is based on the contents, not just the outer filename.

Figure 2: When Archive Peek finds an app or installer, it highlights the useful details.

Archives, Disk Images, and Nested Containers

Archive Peek covers common archives such as ZIP, 7Z, RAR/RAR5, TAR, GZIP, BZIP2, XZ, and Zstandard. It also understands DMG, ISO, CDR, IMG/RAW, virtual-disk formats such as VHD, VMDK, VDI, and QCOW, and the file systems commonly found inside them.

Real files are often layered. An ISO may contain an HFS image; a compressed archive may contain another archive or disk image. Archive Peek follows common nested structures automatically, with a bounded depth, and leaves multiple valid child images visible as folders instead of guessing which one you wanted.

Not every file with a supported extension is guaranteed to open: damaged data, unusual encryption, or an unsupported internal variant can still prevent a preview. The app reports that cleanly and does not fall back to mounting the file.

Password-Protected ZIP and 7Z Files

Encrypted ZIP and 7Z files use a native macOS password dialog. After a correct password is entered, the archive opens in the same file browser or installer view. The password stays in memory only for that preview session and is never saved or copied to the clipboard.

Figure 3: Password entry happens in a separate native dialog, so Finder keeps normal keyboard control.

Choose Which Formats Archive Peek Handles

Quick Look extensions can overlap, especially on a Mac with several archive utilities installed. Archive Peek therefore includes a small main app where each format group can be enabled or disabled. You can let it handle disk images and 7Z files, for example, while leaving ZIP previews to another extension.

Figure 4: Format switches let Archive Peek coexist with other Quick Look extensions.

Install Archive Peek

Open the Archive Peek project page, download the latest DMG from its Releases section, drag Archive Peek to Applications, and open it once. Choose the formats you want, then select a supported file in Finder and press Space.

The project page also contains the source code and full documentation. If Archive Peek is useful to you, please consider giving it a Star—it helps more Mac users discover the project and lets me know that continued development is worthwhile.

The current community build is not notarized by Apple. First try approving it in System Settings → Privacy & Security. If macOS still blocks a copy that you downloaded from the official project page, open Terminal and run:

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xattr -dr com.apple.quarantine "/Applications/Archive Peek.app"
open "/Applications/Archive Peek.app"

The first command removes the downloaded-file quarantine marker; it does not sign the app or change its program code. Only use it for a copy obtained from the official Archive Peek project page or another source you trust.

Archive Peek began as a focused DMG preview experiment. It has since become a more general answer to a small but persistent Finder limitation: sometimes you want to look inside a container without opening, mounting, or unpacking it first.

How It Works

The interface is built with Swift and SwiftUI as a modern Quick Look Preview Extension. A thin Objective-C++ bridge sends the selected file to bit7z 4.1.0 and the official 7-Zip 26.02 handlers, then returns only the metadata needed to build the preview.

For a DMG, Archive Peek opens the disk-image layer, finds an APFS or HFS/HFSX child, and opens that child through a random-access parent stream. That is the important part: the filesystem can be enumerated without mounting the DMG or first writing a raw image to disk. The same bounded traversal handles other archive, partition-table, disk-image, and filesystem layers.

The original Archive Peek code is released under the MIT License. Its bundled parsing dependencies retain their own upstream licenses; the repository includes the corresponding notices and source.

Questions and Answers

Does Archive Peek extract or mount my files?

No. Previews are read-only. Archive Peek does not mount disk images, extract the full archive into a folder, create temporary raw images, or modify the original file.

Which formats should I enable?

Enable the formats for which you want Archive Peek to become the Finder preview provider. If another Quick Look extension already handles ZIP files the way you prefer, you can leave ZIP disabled and enable only DMG, ISO, 7Z, or other groups.

Can it preview password-protected archives?

Yes, encrypted ZIP and 7Z files are supported. Archive Peek asks for the password in a native macOS dialog and keeps it only in memory for the active preview. Other encrypted formats may not be supported.

Why can two files with the same extension behave differently?

An extension such as .img, .iso, or .zip describes the outer container, but the internal filesystem, compression method, encryption, and file integrity can differ. Archive Peek can preview the combinations supported by its parsing backend and reports a clear error for unsupported or damaged files.

What should I do if Archive Peek does not appear in Finder?

Open Archive Peek once, confirm that the file’s format is enabled, then check System Settings → General → Login Items & Extensions → Quick Look and enable Archive Peek. Closing and reopening the Finder preview may also be necessary after changing format settings.

To create a polished installer image for your own Mac app, see How to Make a macOS DMG Installer with a Custom Background.
To remove mounted installer volumes after a busy setup session, see Eject Disk Images.

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