User Manual - Duplicate Wizard

1. Introduction

Duplicate Wizard is a macOS application for finding and managing duplicate files. It helps you identify files that have identical content, even if they have different names or are stored in different locations.

What Problem Does It Solve?

Over time, duplicate files accumulate on your computer. This happens when you:

Copy files between folders and forget about the originals
Back up files manually to multiple locations
Import the same photos or documents more than once
Migrate data from old drives without cleaning up

Duplicate Wizard finds these files by comparing their actual content, not just their names. Two files with different names but identical content are duplicates. Two files with the same name but different content are not.

How It Works

Duplicate Wizard uses a multi-stage detection process:

Size comparison: Files with different sizes cannot be duplicates, so these are filtered out immediately. Empty files (0 bytes) are also excluded — since all empty files have identical (absent) content, they would be falsely grouped as duplicates despite being unrelated
Content verification: Files that match in size are verified using SHA256 hashing of strategic portions of the file content

This approach is both fast and reliable. The size filter eliminates the vast majority of non-duplicates instantly, and a partial content hash verifies the remaining candidates.

2. Core Concepts

Content-Based Detection

Duplicate Wizard identifies duplicates by their content, not their names. This means:

Two files named photo.jpg and backup_photo.jpg are duplicates if their content is identical
Two files both named document.pdf are not duplicates if their content differs

Two Modes of Operation

Two-Folder Comparison: Compare two different folders to find files that exist in both. Useful for:

Comparing a backup to the original
Finding files duplicated across drives
Cleaning up after migrations

Single-Folder Scan: Find duplicate files within a single folder. Useful for:

Cleaning up a downloads folder
Finding duplicates in a photo library
General folder cleanup

Terminology

Term	Meaning
Folder A / Folder B	The two folders in a two-folder comparison
Source folder	The folder being scanned in single-folder mode
Other Copies	Duplicate files found within the same folder
Detail Panel	The dedicated panel in single-folder mode for reviewing and resolving duplicate groups
Duplicate Group	A set of files with identical content
Resolved Group	A duplicate group where exactly one copy is kept and all others are marked
Recommended	The copy the scoring engine identifies as the best to keep
Matches	Files in one panel that match selected files in the other panel
Marked	Files you have selected for potential deletion

The Three-Step Workflow

Duplicate Wizard guides you through three steps:

Select Folders: Choose which folder(s) to scan
Compare & Mark: Review duplicates and mark files you want to remove
Review & Delete: Final review before moving files to Trash

You can move between these steps at any time. The app prevents accidental deletion by requiring explicit confirmation.

3. Getting Started

Opening Folders

There are two ways to add folders to Duplicate Wizard:

Drag and Drop: Drag a folder from Finder directly onto either panel's drop zone.

Select a Folder Button: Click the "Select a folder" button to open a file picker.

Folder Selection Rules

Duplicate Wizard will not scan:

System folders (Applications, Library, System)
The root of a startup volume
Folders you do not have permission to read

External drives and network volumes are supported, but folders on read-only volumes can be scanned but not modified.

Unloading Folders

To remove a folder from a panel, click the "X" button next to the folder path.

4. Two-Folder Comparison Mode

What It Is

Two-folder comparison finds files that exist in both Folder A and Folder B. It answers the question: "Which files in these two folders are duplicates of each other?"

When to Use It

After migration: You copied files from an old drive and want to know which ones are duplicates of files already on your main drive
Backup verification: Compare a backup folder to the original to see what overlaps

What Is Included

Files in Folder A that have identical content to files in Folder B
Nested folders are scanned recursively

What Is Excluded

Duplicates within the same folder are not shown
To find internal duplicates, use Single-Folder Scan Mode

Understanding the Results

After scanning, the left panel shows duplicate files from Folder A, and the right panel shows duplicate files from Folder B. Selecting a file in one panel highlights its matches in the other panel.

5. Single-Folder Scan Mode

What It Is

Single-folder scan finds duplicate files within a single folder. It answers the question: "Which files in this folder have copies elsewhere in the same folder?"

How to Activate It

Load a folder into one panel and click "Scan for Duplicates" without loading a second folder. The app will automatically switch to single-folder mode.

When to Use It

Downloads cleanup: Find files you downloaded multiple times
Photo library: Identify duplicate photos
General cleanup: Find wasted space from internal duplicates

How Duplicates Are Displayed

In single-folder mode with the Duplicates view active, one panel shows the source folder tree and the other shows the Detail Panel — a dedicated interface for reviewing and resolving duplicate groups.

The Detail Panel

The detail panel has two states: Groups Overview and Group Focus.

Groups Overview

The default state shows all duplicate groups as a scrollable list. At the top, a progress header displays “X of Y resolved” with a progress bar and the total recoverable space.

Filter pills let you narrow which groups appear:

All: Shows every duplicate group
Remaining: Shows only groups that still need a decision
Resolved: Shows only groups where one copy has been kept

Each group row shows:

A thumbnail of the first file in the group
The filename and copy count badge (e.g., “2/3” meaning 2 marked out of 3 copies)
The recoverable space (how much space marking the extra copies would free)
A “Resolve” button on unresolved groups — clicking it lets the app recommend which copy to keep and marks the others for deletion
A “Reset” button on resolved groups — clicking it clears all marks in the group, returning it to an unresolved state

At-risk groups (where all copies are marked for deletion) are highlighted with a red background.

The progress header includes a “Resolve All” button to batch-resolve all visible unresolved groups at once (Full Version only). As groups are resolved individually, the label updates to “Resolve X” showing how many remain. A spinner appears while the batch operation runs.

Group Focus

When you select a duplicate file in the tree, the detail panel switches to Group Focus, showing detailed copy cards for the selected group.

Header bar:

Back button labeled “All Groups” to return to the overview
The group title (e.g., “1 group selected”)
A “Resolve Selected” button to auto-resolve the focused group(s)

Each copy card shows:

A copy number badge (#1, #2, #3)
The filename, with a “Recommended” tag on the highest-scored copy
The parent folder path
The modification date
An action button:
- “Keep this” (on unresolved copies) — clicking it marks all other copies in the group for deletion
- “Kept ✓” (on the sole unmarked copy in a resolved group)
If a name or size filter is active and hides a copy, the card shows a “Hidden by filter” indicator and the action button is disabled

Score comparison table: An expandable section below the copy cards shows the scoring breakdown for all copies. The table has columns for each enabled criterion (e.g., Clean Name, Newest Date, Shallowest Path, Shortest Name) and a total score. The recommended copy’s row is highlighted.

Group footer warnings:

At-risk warning (red): Appears when all copies in the group are marked for deletion, advising you to reset and keep at least one
Partial marks warning (orange): Appears when some copies are marked but the group is not fully resolved

You can select multiple files from different groups in the tree (Cmd+click). The detail panel shows all relevant groups stacked with dividers.

Navigation:

Click a copy card to select that file in the tree (Cmd+click to add, Shift+click for range)
Click the “All Groups” back button to clear tree selection and return to overview

Review Mode in Single-Folder Mode

When you switch to the Review & Delete step in single-folder mode, the detail panel is replaced by a split view showing all groups that have marked files.

Each group is displayed as a row with:

An info bar showing the filename, file size, and a “View Group” button that navigates to the group’s copy cards in Group Focus
Two columns:
- Left column (Keep): Files you are keeping (unmarked), shown with their folder path hierarchy
- Right column (Delete): Files marked for deletion, shown with their folder path hierarchy
A warning indicator if all copies of a group are marked (no original will be kept)

The same filter pills (All / Remaining / Resolved) are available to narrow which groups appear. When you click “View Group” to inspect a group’s copy cards, a “Back to Review” button lets you return to the review split view.

Recommendation Preferences

The app scores each copy using four criteria to suggest which file to keep. You can configure these in Preferences (Cmd+,):

Criterion	Default Weight	Description
Clean Name	3	Prefers files without copy suffixes like “(1)”, “-copy”, or trailing numbers
Newest Date	2	Prefers the most recently modified file (invertible: prefer oldest)
Shallowest Path	2	Prefers files with fewer folder nesting levels (invertible: prefer deepest)
Shortest Name	1	Prefers shorter filenames, which are more likely the original

For each criterion you can:

Enable or disable it
Adjust the weight (0–5) to control its importance relative to other criteria
Invert the direction (for date and path criteria) — for example, prefer the oldest file or the most deeply nested path

Click “Reset to Defaults” to restore the factory settings. Changes apply to the next Resolve or Resolve All operation. The score comparison table in Group Focus reflects your current configuration.

6. Filtering Your View

Duplicate Wizard provides several ways to filter what you see.

View Modes

Each workflow step shows a different view of your files:

All Files (Select Folders step): Shows every file in the loaded folders. This is a read-only view before scanning.

Duplicates Only (Compare & Mark step): Shows only files that have at least one duplicate. Available after scanning.

Review Marked (Review & Delete step): Shows only files you have marked for deletion. Available when you have marked files.

Duplicate Wizard has two kinds of filters: pre-scan filters determine which files are loaded into the tree (changing them requires reloading), and real-time filters apply instantly to the current view.

File Type Filter (Pre-Scan)

Limit the scan to specific types of files:

Images: Photos and graphics
Videos: Movie files
Audio: Music and sound files
Documents: PDFs, office documents, and text files

These categories are based on macOS Uniform Type Identifiers, which classify files by their type metadata rather than their extension. You can select multiple categories.

You can also add custom file extensions to include or exclude (Full Version only).

Size Filter (Real-Time)

Requires Full Version

Filter files by size thresholds:

Smaller than: Show only files below a certain size (10 MB, 100 MB, 1 GB)
Greater than: Show only files above a certain size (10 MB, 100 MB, 1 GB)

This helps focus on large files that waste the most space, or filter out small files when looking for major duplicates.

Name Search (Real-Time)

Type in the search field to filter files by name. The filter applies in real time as you type. Only files whose names contain your search text are shown.

To clear the search, delete the text in the search field.

7. Cross-Panel Highlighting

What It Does

When you select one or more files in one panel, Duplicate Wizard highlights their duplicates in the other panel. This helps you see exactly which files match.

How to Use It

Click a file in either panel to select it
The other panel automatically filters to show only files that are duplicates of your selection
A status banner shows how many matches are displayed

Selecting Multiple Files

Hold Command (Cmd) while clicking to select multiple files. The other panel shows the combined matches for all selected files.

You can also click a file and drag over other files to select a range. This selects all visible files in the drag area, even across folders, without expanding or collapsing them.

Clearing the Selection

To return to the normal view, press Escape or click the "Clear selection" button in the panel.

8. Scanning for Duplicates

Starting a Scan

After loading folder(s), click the "Scan for Duplicates" button. The app scans both panels simultaneously.

Scan Progress

During scanning, you will see:

Progress bar with file count
Estimated files remaining

Canceling a Scan

Click the "Cancel" button during a scan to stop it. Any partial results are discarded, and you return to the folder selection state.

Refreshing Folders

If files on disk change after loading (added, deleted, or modified by other apps), click the "Refresh" button next to the folder path to reload the tree. If a scan was previously run, the app automatically re-scans after refreshing.

9. Previewing Files

Duplicate Wizard offers multiple ways to preview files before deciding what to delete.

Quick Look

Press the Space bar with files selected in the file tree or in the Comparison Gallery to open macOS Quick Look. This shows a full preview of the file using the system preview.

You can also double-click a file to open Quick Look. Double-click works in the file tree, Comparison Gallery, and thumbnail previews.

Inline Preview Panel

Below each file tree, you can enable an inline preview panel that shows thumbnails of selected files.

To toggle the preview panel, click the "Thumbnails" button in the action bar.

Comparison Gallery

The Comparison Gallery is available in two-folder comparison mode only. In single-folder mode, the Detail Panel provides the equivalent comparison and resolution workflow (see Single-Folder Scan Mode).

To open the gallery, click “Comparison Gallery” in the action bar. This opens a separate window showing each duplicate set as a row. Only sets with files in both folders are shown.

Each row displays:

A header with the filename, file size, total copies count, and an at-risk warning badge if all copies are marked
A thumbnail of the first file (resizable column)
A two-column copy layout: Folder A copies on the left, Folder B copies on the right

Each copy card shows the filename and parent folder path, dates, and a mark/unmark button. Marked copies appear with a red tint and reduced opacity. Each column header includes an Actions menu with “Mark All” and “Unmark All” options (Full Version only).

You can mark files for deletion directly from the Comparison Gallery.

Detached Preview Windows

Click the detach button on an inline preview panel to open it in a floating window. This lets you keep previews visible while navigating the file tree. When the main window is too small for inline previews, the Thumbnails button becomes a menu where you can choose which panel to preview in a detached window.

10. Marking Files for Deletion

What Marking Does

Marking a file indicates you want to remove it. Marking does not delete or move anything. Marked files are only moved to Trash after you explicitly confirm in the Review step.

How to Mark Files

Hover over a thumbnail in the preview panel or Comparison Gallery and click the trash icon
Select one or more files and click "Mark selected"
Select files and press the M or Delete key
Right-click and choose "Mark for deletion"
Right-click a folder and choose "Mark folder contents" (Full Version only)
Use "Mark all files in this panel" from the Actions menu (Two-folder mode only, Full Version only)
Click “Keep this” on a copy card in the Detail Panel — this marks all other copies in the group for deletion (Single-folder mode)
Click “Resolve” on a group row in the Detail Panel overview — the app recommends which copy to keep and marks the others (Single-folder mode)
Click “Resolve All” / “Resolve X” in the overview header to batch-resolve all visible unresolved groups (Single-folder mode, Full Version only)

How to Unmark Files

Hover over a marked thumbnail and click the undo icon
Select marked files and click "Unmark selected"
Select files and press the U key
Right-click and choose "Unmark for deletion"
Right-click a folder and choose "Unmark All Folder Contents" (Full Version only)
Use "Unmark all files in this panel" from the Actions menu (Two-folder mode only, Full Version only)
Use the "Unmark all" button in the action bar to clear all marks (visible in Review & Delete mode only)

Marking vs Selecting

Selecting (highlighted row): Temporary. Used for navigation, preview, and cross-panel filtering.

Marking (trash icon / marked state): Persistent. Indicates files you want to delete. Survives changing view modes.

11. Review and Delete

The Review Step

Before any files are deleted, you enter the Review step. This shows only the files you have marked.

In two-folder mode, both panels filter to show only marked files in each folder.

In single-folder mode, the review step shows a split view with all groups that have marked files. Each group displays two columns — files you are keeping on the left and files marked for deletion on the right — with a “View Group” button to inspect the group’s copy cards. See Review Mode in Single-Folder Mode for details.

Review your selections carefully. You can:

Unmark files you want to keep
Preview files one more time

Move to Trash

Click "Move to Trash" to move marked files to the Trash. A confirmation dialog appears showing:

Number of files to be deleted
Folders affected
Total disk space that will be freed

Risk Detection

Duplicate Wizard provides visual warnings when all copies of a duplicate set are marked for deletion:

Thumbnail alert badges: An orange warning triangle appears on affected file thumbnails in the Comparison Gallery, inline Preview Panel, and detached preview windows. This makes at-risk files immediately visible as you mark them.
Locked file badges: Files that are immutable (system-locked) display an orange lock icon on their thumbnails, indicating they cannot be moved to Trash.
Detail panel warnings: In the detail panel, at-risk groups show an orange warning banner with advice, and their overview rows have a red background to flag them for attention.
Confirmation dialog: Before deletion, a final warning shows "No original copy will be kept", how many files have no remaining backup, and recommends reviewing before proceeding.

These layered safeguards help prevent accidentally deleting files you meant to keep.

After Deletion

After files are moved to Trash:

The folders are cleared and you can load new folders from scratch
A notification confirms how many files were moved to Trash
The "Recently Deleted" button appears in the action bar, giving access to the recovery panel

12. Recently Deleted (Recovery)

What It Is

Recently Deleted shows files you moved to Trash during the current session. When Duplicate Wizard moves files to Trash, macOS does not track their original location — so the Trash's "Put Back" option is not available for these files. The recovery panel solves this by remembering where each file came from and restoring it directly to its original folder. This list is only available until you close the app — after that, the files remain in Trash but the original folder reference is lost.

How to Access It

Click "Recently Deleted" in the action bar. A panel opens showing all recoverable files.

Restoring Files

Click "Restore" next to any file to return it to its original location.

Click "Restore All" to recover all files at once.

Recovery Status

Each file shows its recovery status:

Recoverable: File is still in Trash and can be restored
Not recoverable: File was permanently deleted or moved

13. Keyboard Shortcuts

Key	Action
`Space`	Open Quick Look for selected files
`M`	Mark selected files for deletion
`U`	Unmark selected files
`Delete`	Mark selected files for deletion
`Return/Enter`	Toggle selection on highlighted file
`Arrow Up/Down`	Navigate file tree
`Arrow Right`	Expand folder
`Arrow Left`	Collapse folder
`Escape`	Clear selected files in the active file tree
`Cmd + ,`	Open Preferences

14. Free vs Full Version

Free Version

The free version of Duplicate Wizard includes scanning, preview, and basic marking features with these limitations:

Marking limit: You can mark up to 5 files for deletion.

Features not available in Free Version:

Size filter (filter by file size)
Custom extension filter (include or exclude specific extensions)
Mark folder contents (right-click a folder)
Mark all files in panel (Actions menu, two-folder mode only)
Resolve All (batch-resolve duplicate groups in single-folder mode)

This allows you to try the core workflow before purchasing. When you reach a limit, a notification explains how to upgrade.

Full Version

The full version unlocks all features:

Mark unlimited files for deletion
Resolve All: one click to resolve every group using the configured scoring criteria
Size filter for focusing on large or small files
Mark entire folder contents with one click
Mark all files in a panel (two-folder mode)

Upgrading

To upgrade to the full version, click "Upgrade to Full Version". This button appears in the action bar, in the Preferences panel, and in the notification shown when you reach the 5-file marking limit.

The purchase is handled through the Mac App Store. Your purchase syncs across your devices signed into the same Apple ID.

Restoring Purchases

If you reinstall the app or use a new Mac, your purchase is restored automatically when the app launches. If restoration does not happen automatically, open Preferences and click "Restore Purchases."

15. Safety and Limitations

What the App Never Does

No automatic deletion: Files are moved to Trash only after explicit confirmation
No permanent deletion: Files are moved to Trash, never permanently deleted
No modification: Files are never modified, only read
No network transmission: All processing happens locally

Built-In Protections

The app cannot scan system folders
The app cannot scan volume roots
A warning is shown before moving all copies of a file to the Trash
Read-only volumes are detected and moving to Trash is disabled

Limitations

Memory usage: Very large folders (millions of files) may consume significant memory
No live monitoring: External changes (files added/removed by other apps) are not detected automatically — use the Refresh button to reload
Content matching: Files are compared by size and by hashing portions of their content. False matches are extremely unlikely but not impossible.

Recommendations

Review the deletion confirmation carefully, especially the risk warning
Do not empty Trash immediately after deletion; verify first
Keep backups of important files

16. Privacy

Local Processing

Duplicate Wizard processes all files locally on your Mac. No file content or metadata is transmitted anywhere.

Folder Access

The app only accesses folders you explicitly select. macOS may prompt for permission when you first select certain folders.

No Data Collection

Duplicate Wizard does not collect or transmit:

File names or paths
File contents
Usage statistics
Personal information

Sandboxing

The app runs in a macOS sandbox, limiting its access to only the folders you grant permission for.

For the complete privacy policy, see the Privacy Policy page.