Free while we’re in preview

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Copies a tree, then re-reads every file off the disk and checks it byte for byte.

The Mac button is for Apple Silicon. On an older Intel Mac, get this one instead.

One file, both ways. Double-click it for the window. Run the same file from a command prompt with arguments and it behaves as the command-line tool, because the engine is inside it. Nothing else to download and nothing to keep beside it.

Early preview. The window has been built and run, but not yet on a real Windows PC or Mac, so expect rough edges. The engine underneath it is fully tested.

One file — no installer
Runs on your machine, offline
Source code published below

Free while in preview. It isn’t signed yet, so Windows or macOS will ask you to confirm the first time you open it. At launch, CopySure is included in every plan along with the rest of the range.

Verify means verify

copysure copy /media/card /archive/2026 walks the source and, for each file, writes it, then reopens it from the destination, reads it back, and hashes what it actually got. If that doesn’t match the source hash, you get told. It isn’t counted as done and it isn’t silently accepted.

Re-running is safe

Before copying anything, it checks whether the destination already holds a file with the same SHA-256. If it does, the file is skipped. That’s what makes an interrupted job resumable: run the same command again and it picks up where the bytes ran out, rather than starting over or duplicating work.

--workers N sets the parallelism, default 4.

Checking a copy somebody else made

copysure diff <src> <dst> compares two trees by content hash without copying a byte. Use it to audit a job that ran on another machine, or to see what a copy run would actually change before you start it.

Scope

This build is the copy, verify and diff engine. Explorer integration and sync rules are still on the plan, not in the binary. Two commands, no config file.

Reading on the job itself

How to copy a large folder and know every file arrived Copy first, then re-read every file from the destination disk and compare its checksum against the source. ...

The rest of Verified Copy & Sync

Copying that proves it arrived. Read the copy back, move between drives, empty a card safely, and keep the proof.

TransferForge

Vertical Ready

Offload a card, then hand the client a manifest proving every file arrived.

MoveGuard

Pro Ready

Moves files, then proves the copy landed intact before it deletes the original.

SyncProof

Team Ready

Copies one build to three shares at once and says which share came out bad.

Advanced & technical details Command-line builds, source code, checksums and a recorded session — for developers and IT teams

A working CLI prototype of the core engine: parallel copy with mandatory post-copy SHA-256 verification, resumable jobs (already-matching files are skipped), and a standalone diff mode. Explorer integration and sync rules are still on the roadmap.

Naming status

Working name only — brand verdict **CAUTION** (Medium). Collision: CopySure. Could keep only after trademark/database check.

What it draws on

Existing paid software whose best ideas shaped this program: TeraCopy Pro, Beyond Compare, SyncBackPro, Copywhiz.

Command line

There is nothing extra to install. The program you download is the command-line tool as well: give it arguments instead of double-clicking it and it runs as one, with its output on your terminal. The standalone builds below are the same engine on its own, for machines where you would rather not ship a window at all.

CopySure — checksum-verified copy

Usage:
  copysure copy <src> <dst> [--workers N]
  copysure diff <src> <dst>

Recorded from the shipped binary, not written by hand.

Windows (amd64) macOS (Apple Silicon) macOS (Intel) Linux (amd64)

Source

Every file the program is built from:

console.go · console_test.go · guided.go · main.go

SHA-256 checksums · build instructions & scope notes · full build plan

CopySure

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