• SCAN → “Add folder…” → pick a folder in Finder. DeDuck inventories just that folder; nothing else is touched.
• Re-run “Add folder…” or “Rescan all…” anytime — unchanged files are skipped automatically.
• While scanning, the top bar shows progress, file count, size, ETA, and Pause / Stop.

• Scan — the folders you've scanned (✕ removes DeDuck's index only, never your files), accurate categorization (Images, Videos, Audio, Documents, Code & scripts, Metadata, System Clutter, Archives, Other), plus an All files browser (Sort, File-type filters, List / Icon / Thumbnail views, Reveal in Finder) and Collections, Largest folders and Largest files.
• Dedupe — Detect Dupes, then tick the copies to clean up (Move to Trash or Quarantine). Pre-library cleanup decision lets you review and clean first or 'Build Library as-is'. Zero permanent deletion.
• Compare — match two scanned folders by content (hash), filter by Matched / Unmatched / Conflicts, and reconcile additively with persistent Undo and instant auto-refresh.
• Library — build, organize, disk-sync, and merge curated master libraries with multi-folder batch actions, Recent Scans, and safe database removal.
• Backups (3-2-1) & Cloud Reconciliation — symmetrical backup protection (Library or Folders → External drive or Cloud), client-side AES-256 encrypted cloud backups, and read-only Google Drive reconciliation that bypasses macOS File Provider placeholder limitations.
• Activity — job status, integrity checks, recommendations, reports, quarantine restore, and storage & history.
• Help & Settings — quick reference guide, core principles, and license & device management.

1. Dedupe → Detect Dupes. DeDuck rescans, then finds byte-identical copies (Exact). Tick Include Similar Photos to also group visually-similar images (Similar). Exact and Similar never overlap.

2. Pre-Library Decision: When creating a library from folders containing duplicates, DeDuck lets you choose whether to review and clean them first or Build Library as-is without altering your source files.

3. Transparent Keepers: Non-destructive safety means similar photos and duplicates are never automatically deleted. Keeper recommendations are transparent, and you can switch keepers anytime.

4. Tick the copies to clean up — the keeper stays. “Show only ticked” narrows the view to the marked copies.

5. Clean up… → Move to Trash or Quarantine (undoable, restorable from Activity). DeDuck NEVER permanently deletes your personal files.

6. A CSV audit report is written for every cleanup and compare/reconcile operation.

Pick two scanned folders (A and B) and Compare. DeDuck rescans both first, then matches by content (hash), so a file counts as present even if it was renamed or moved. Pick “Add folder…” in either picker to scan a new one. “Clear all” next to Compare resets the view.

• 'Show' dropdown filter: Switch between All · Unmatched (no content match on other side) · Conflicts (same path, different content) · Matched. One shared File-types filter + Search; each side pages independently.
• Reconcile folders header: Make A = B (mirror both ways), Fill A (A ⊇ B) (arrow left into A), or Fill B (B ⊇ A) (arrow right into B). All copies are additive — they mirror the source's folder structure and keep both files on conflicts with a ~from suffix; nothing is moved or overwritten.
• Selective copy: Tick individual rows in a pane, then Copy selected → to copy just those.
• Automatic refresh & persistent Undo: Compare automatically refreshes immediately after copying. Use the persistent Undo button next to Clear all (and in the top status banner) to safely move copied destination files to Trash while leaving originals completely untouched.
• Audit trail & CLI: Generates a compare-reconcile-*.csv report logged under Activity. Run compare from the command line anytime: deduck compare A B [--mode fill_a|fill_b|both] [--apply].

A library is a DeDuck-owned master copy (DDL<n>_<name>) holding an organized copy of your files — your originals are never touched, deleted, or moved. You can have several.

• Multi-Selection & Bulk Actions: Checkboxes on scanned folders and libraries let you perform batch operations. Use Select all or Clear in the section header.
• Folder Bulk Actions: When folders are checked, use the action bar to [Scan], [Compare], [Create Library] from selected folders, [Merge…] into an existing library, or [Remove] from DeDuck's index.
• Strict Semantic Guarantee: "Nothing happens to an unselected folder." Single-folder actions build strictly from that folder; multi-selection builds only from checked folders.
• Merge Semantics: Merge into Library copies files from selected scanned folders into a chosen destination library without deleting original scanned files. Library-to-library merge folds source libraries into an explicit destination library with duplicate summary preview and quarantine option.
• Clean Layout Organization: Files are neatly organized by asset type into Images, Videos, Audio, Documents, Code & Scripts, Metadata (.aae, .xmp), System Clutter (.lrprev, cache files), Archives, and Other. Or organize by year/month, flat, or 'Preserve folder structure'.
• Safe Removal vs Deletion: Remove from DeDuck removes only DeDuck's database records. Physical library folders and files on disk are completely preserved.
• Disk Sync & Restore: Refresh from folder on disk syncs changes made directly in Finder; Restore… discovers libraries on disk and registers them back into DeDuck.
• Recent Scans: Recent scans appear directly on the Library tab with one-click Rescan, Compare, Create Library, and Remove actions.

DeDuck implements the gold-standard 3-2-1 Backup Strategy to protect your personal files: 3 copies (primary master + 2 backups), across 2 different media (local disk + external volume), with 1 offsite copy (secure cloud).

• Symmetrical Source & Destination: Select any Master Source (a curated DeDuck Library or Scanned folders) and any Backup Destination (an external drive or Cloud provider).
• Encrypted Cloud Backups: Protect offsite uploads with client-side AES-256 encryption and password protection before files leave your machine.
• Verify Protection & Coverage Audit: Audits all files across master sources and backup destinations to ensure complete coverage, highlighting any missing, unprotected, or at-risk copies.
• Google Drive Cloud Reconciliation: Connect Google Drive securely using a strict read-only metadata scope (drive.metadata.readonly) to reconcile local recovery folders against the authoritative cloud inventory.
• Bypass macOS File Provider: Directly queries Google Drive API to discover files that macOS File Provider incorrectly reports as 0 files / 0 B due to dataless cloud placeholders.
• Reconciliation Buckets: Inspects full recursive cloud hierarchy and verifies MD5 checksums, categorizing files into: Already in cloud · Local only · Cloud only · Conflicts · MD5 verified.
• Strictly Read-Only Guarantee: Cloud reconciliation never modifies, overwrites, deletes, or uploads files — it provides complete visibility without risk.

Generate a shareable Digital Clutter Report — a tidiness grade, reclaimable space, what's using space by type, and your biggest duplicate groups — from Activity → Reports, the Library tab, or deduck clutter. Open it to Print / Save as PDF.

• Reports save to ~/Documents/DeDuck Assets/Reports/. Generation is on-demand by default; you can opt into auto-generating one after each scan in Settings → Reports & History Preferences.
• A cleanup and compare/reconcile CSV report is written after each action (on by default; toggleable).
• Auto-keep history & reports: Configurable retention (newest 10 / 20 / 50 / 100, or Everything) caps Recent scans, Changes, File actions and saved Reports — older entries prune automatically after each scan.
• Clear reports: Removes all saved reports at once — Clutter Reports (HTML) and cleanup data dumps (CSV).

• ~/Documents/DeDuck Assets/ — Reports (HTML & CSVs), Libraries (organized copies), Quarantine (isolated batches), and Similar.
• ~/Library/Application Support/DeDuck/ — internal database, logs and license (Activity → Storage & history → “Wipe all inventory” resets it).

Nothing is written to your scanned drives.

• Device limits: DeDuck registers each machine with your license (2 devices for Pro; 5 for Studio). Check active machines under Settings → License, Devices & Upgrades.
• Deactivate this Mac: In Settings → License card, click 'Deactivate this device'. This instantly releases the slot — no need to contact support.
• Reactivating / Moving: On your new Mac, open Settings → Devices & Upgrades → 'Enter/Update key' and paste your license key to reclaim a slot.
• 14-day offline grace: Active Pro & Studio users can work completely offline for up to 14 days without an internet connection.

• System temp files (Office ~$…, *.tmp) are ignored automatically.
• Scanning the whole Mac (/) is discouraged — pick specific folders; the app warns you.