SmartFolder

What is SmartFolder?#

Your Mac fills up. You don't know why. Finder doesn't help you figure it out, so you end up downloading three different cleanup apps that each cost $20 a year and want a subscription. SmartFolder is the alternative — a built-in toolkit that answers the three questions you actually need answered:

• Where are my duplicate files? Same photo saved in three folders, the same PDF downloaded twice — SmartFolder finds them.
• What's taking up the most space? The biggest individual files on your disk, ranked from largest to smallest.
• What apps can I get rid of — completely? Including all the leftover settings and caches that normally stay behind in ~/Library when you drag an app to the Trash.

Together, these replace what most people use Gemini, DaisyDisk, and AppCleaner for. And every part of it runs on your Mac — no account, no analytics, no cloud.

Two Ways to Start a Scan#

Open the sidebar, find the Smart Folders section, and click Duplicates, Large Files, or App Cleaner. This scans your home folder by default — usually what you want.

If you'd rather scan one specific folder (a Downloads folder that's gotten out of hand, an external drive), right-click the folder and choose Smart Folder ▸ Scan Duplicates or Scan Large Files. The scan only looks inside what you picked.

Scans don't modify any files — they just look. You can stop one at any time by clicking somewhere else, or restart it with the rescan button (↺) in the header.

Finding Duplicates#

Two files are duplicates only if their contents are byte-for-byte identical — same name is not enough, same size is not enough. Seiz takes a digital fingerprint of every file and matches them that way, so you never end up deleting something that looked like a copy but wasn't.

Scanning is fast: a folder with a few thousand files usually finishes in seconds. The clever part is that Seiz only does the slow deep comparison on files that already passed a quick size + sample check, so most files are ruled out instantly.

Reading the results#

Duplicates are organized into groups. Each group is a set of files that match each other. One file in each group is labeled Original and the others are labeled Copy, but that's just to make the list readable — Seiz isn't saying the “Original” one is more important. Pick whichever copy you actually want to keep.

Hover any row and two buttons appear: a folder icon to open that file's location and a trash icon to delete just that one file. You can also tick rows to select them and use the Trash Selected button to delete several at once. The bar at the top of the selection shows how much space you'll reclaim.

Sort and Auto-select#

Two sort modes for the groups: By Space Saved (the default — biggest space wins first) or By Count (groups with the most copies first, useful for spotting files that have spiraled out of control).

The Auto-select menu offers a Keep Shortest Path option that, for every group, ticks every copy except the one with the shortest folder path. The intuition: if a file lives at ~/Pictures/sunset.jpg that's probably your real one, while ~/Pictures/Old Backups/iPhone 2019/photos/sunset.jpg is the one you forgot about. Auto-select doesn't delete anything — it just makes the selection. You still have to click Trash Selected to commit.

Finding Large Files#

The Large Files scan ranks individual files from biggest to smallest. Each row has a colored size bar — blue for smaller files, orange for medium, red for the heaviest hitters — so the worst offenders jump out visually.

At the top of the view is a size threshold — by default 100 MB, meaning anything smaller is hidden. You can switch it to 10 MB, 50 MB, 500 MB, or 1 GB depending on how aggressive you want to be. Changing the threshold is instant; Seiz already has all the data and just re-filters in place.

Hovering a row gives you the same two buttons as in duplicates: open in folder, or trash.

Uninstalling Apps Properly (App Cleaner)#

When you drag an app to the Trash on a Mac, only the app itself is removed. Its caches, preferences, login items, and saved data live in ~/Library and stay there forever — sometimes for years. App Cleaner finds the full footprint of every installed app and removes all of it in one step. It also surfaces leftovers from apps you uninstalled long ago.

Open it from the sidebar under Smart Folders ▸ App Cleaner. The view has two tabs: Installed Apps (everything currently on your Mac, sorted by size) and Orphaned Files (leftovers from apps you no longer have).

The Installed Apps tab#

Each row shows an app, its size, and when you last used it. Click the chevron to expand a row — Seiz scans ~/Library on demand and lists every related file grouped by category: caches, preferences, application support, containers, login items. The header updates from the bundle size (e.g. “280 MB”) to the full footprint (“417 MB”) so you can see the real cost of keeping the app.

Search by app name, sort by size or last-used date, and ⌘-click to select multiple apps for batch uninstall.

Uninstalling#

Click Uninstall on a row, in the selection bar, or from the right-click menu. Seiz shows a confirmation telling you exactly what will be removed and how much space you'll free up. After you confirm, everything goes to the macOS Trash (not permanent delete) and a 15-second undo toast appears at the bottom — click Undo and every file is restored to where it was.

A few safeguards worth knowing about:

• Running apps can't be uninstalled. Quit them first. There's no force-quit shortcut — too easy to lose unsaved work.
• macOS system apps don't appear at all. You literally can't use App Cleaner to break your Mac.
• MDM-managed apps show a 🔒 badge and the Uninstall option is hidden — your IT department's rules are respected.
• Partial failures are explicit. If a system file needs admin rights and you cancel the password prompt, Seiz tells you which files were trashed and which weren't — no silent half-uninstalls.

For the most complete scan, grant Seiz Full Disk Access in System Settings — without it, macOS hides the contents of ~/Library/Containers and Seiz shows a banner explaining what was skipped.

Bonus: the Applications folder#

When you're browsing /Applications like a normal folder in Seiz, deleting an app file automatically uses the Uninstall flow instead of a plain trash. Right-click an app and the menu shows Uninstall… instead of “Move to Trash”; ⌘⌫ opens the same confirmation; even dragging the app toward the Trash triggers it. Non-app files (installer disk images, folders) still trash normally.

The Orphaned Files tab#

Even if you've been careful, you almost certainly have leftover files in ~/Library from apps you uninstalled years ago. Orphaned Files finds those and groups them by what app they probably came from, with the total size you can reclaim.

Detection is intentionally cautious: Seiz skips anything that looks like a system component, and only flags entries that have a real app-style identifier. Some genuine orphans may slip through, but you won't see false accusations against files that are actually in use. Cleaning works exactly like uninstalling — confirm, trash, 15-second undo.

Filtering Results#

After a scan, the search box and filter button (the funnel icon) help you narrow large result sets without rescanning. You can filter by file type (images, video, audio, documents, archives), by size range (over 1 GB, 100 MB–1 GB, 10 MB–100 MB, under 10 MB), or by folder (any of the top-level folders inside your scan root). Active filters appear as removable chips above the results, with a Clear All button.

The same popover also lets you tell Seiz to skip certain folders or extensions entirely during scanning. Seiz ships with about two dozen technical folders (node_modules, .git, DerivedData) already excluded by default — these are mainly relevant if you're a developer; for everyone else the defaults just work.

Selecting Multiple Files#

Click rows to tick them, ⌘A to select everything visible (filters and search are respected, so you can narrow first then select-all just the matches). When anything is selected, a sub-header slides in showing how many you picked and how much space you'll save — something like “7 selected · 1.2 GB” — plus Deselect All and a red Trash Selected button. Trash Selected always asks for confirmation, and the undo toast gives you 15 seconds to take it back.

For duplicates, there's also a Trash all copies shortcut that picks one file per group automatically and trashes the rest. This button is intentionally hidden until you've expanded at least one group — Seiz wants you to look at the kind of files it found before bulk-deleting on autopilot.

Privacy#

Cleanup apps see everything you have, so they have to be trustworthy. SmartFolder runs entirely on your Mac. No analytics, no “phone home,” no account, no cloud. Your file names, contents, and scan results never leave the device. The scanning view even includes a small reminder of this — “All scanning happens on your Mac — nothing leaves this device” — because it's a fair thing to want to know.

Next Steps#

• Multi-Pane Layouts — open a second pane to compare a duplicate group against where you actually want to keep the file.
• Command Bar — start a scan with ⌘K instead of clicking through menus.
• Keyboard Shortcuts — full reference for everything you can do without the mouse.