MERLIN STUDIO
VENTURE DOSSIER

ScratchManager

More room on your Mac

A Mac app that moves bulky, rebuildable app storage, like caches and build files, onto an external SSD. Unplug the drive and the Mac quietly covers for it. Plug it back in and everything moves home.

DOSSIER

  1. 01Why Merlin wanted to build it
  2. 02The partnership
  3. 03The product
  4. 04Product decisions
  5. 05How it is built
  6. 06Evidence and progress
01 · WHY MERLIN WANTED TO BUILD IT

Xcode, Unity, Photoshop and AI coding tools fill a Mac fast, and storage upgrades are expensive. Moving app data by hand works until a cable comes loose. The gap is not the idea, it is doing it safely.

02 · THE PARTNERSHIP

Merlin-originated, like Scaffolds. Merlin designs it, builds it and will sell it. A distribution partner in the Mac, creative or developer space is the open seat.

  • 01In use on Merlin's own Mac before anyone else's
  • 02Designed, built and to be sold by Merlin
  • 03Nineteen app profiles, from Xcode to Claude
03 · THE PRODUCT

A six-step setup, a scan that shows what can move, and one button per app: Use SSD, or Move Back to Mac. A menu bar helper watches the drive and handles the rest.

In private testing on macOS. Not yet on sale.

The ScratchManager scan: 74 apps scanned, 8.2 GB of potential savings and recommended actions
The scan: what can move now, what needs closing first, what needs a person.

Guided setup

Six steps: welcome, choose the drive, prepare it, test its speed, review, install.

A savings scan

Measures your apps and sorts them: ready to move, close first, needs review, or view only.

One button per app

Use SSD, or Move Back to Mac. Logins, settings and profiles never leave the Mac.

Unplug without fear

Pull the drive and only its apps fall back to the Mac. Reconnect and the data is checked and moved home.

More than one drive

Every SSD gets its own identity, so renaming one changes nothing. Each app belongs to exactly one drive.

A speed test that advises

A quick test rates the drive and says which kinds of work suit it.

1 / 6

CAPTURED FROM THE CURRENT BUILD

Setup step one: give your Mac more breathing room
Setup, step one. The promises come first.
Cursor's storage page with Use SSD and Move Back to Mac buttons and the folders it watches
One app, two buttons. Login and settings stay on the Mac.
Setup step two: choosing which external SSD to use
Pick the drive. Each one keeps its own identity.
Setup step three with erase selected: type ERASE to confirm, and Continue stays disabled
Erasing a drive means typing the word. Internal disks are refused.
Setup step five: a review of the drive, preparation and automation before install
Review everything before anything happens.
Setup finished: ScratchManager is ready
Ready. The menu bar helper takes it from here.
04 · PRODUCT DECISIONS
01

Copy, verify, then switch

Data is copied and checksummed before anything points at it. The original waits until the new home is proven, and every step can roll back.

02

Every move is journalled

A crash or a pulled cable mid-move is recovered on the next start. Nothing is left half-done.

03

Recovery is never paywalled

An expired trial blocks new moves only. Fallback, repair and Move Back to Mac always work.

04

Cautious by default

Browsers, virtual machines and cloud drives are view-only. Browser moves stay off until real unplug tests pass.

05

The app list is data, not code

Each app profile is a plain description. It cannot run commands, and every path is checked against protected places.

05 · HOW IT IS BUILT
  • Swift
  • SwiftUI
  • AppKit
  • Liquid Glass
  • Disk Arbitration
  • FSEvents
  • zsh
  • macOS 14+

Five tools, one model

The app, the menu bar helper and three command-line tools share a single Swift model, so they cannot disagree.

Fixed paths, moving targets

Apps always point at the same place. That place leads to the drive, or to a fallback for that drive. One missing SSD never touches another's apps.

Built without Xcode

A plain build script compiles everything. About 4,400 lines of Swift, with tests that simulate an interrupted move.

1 / 3
06 · EVIDENCE AND PROGRESS

Version 1.2.3 is installed and in use on Merlin's own Mac. Signing, notarisation, payments and physical unplug testing come before a public release. No sales figures yet, because nothing is on sale yet.

Reach the people who need this?

If you have a route to Mac creatives or developers, the evaluator will work out whether there is a venture in it.

Start a venture