Verified Copy & Sync

CopySure

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

Free right now. No account, no card

Get CopySure free → Windows & Mac · one file, nothing to install

Preview

1 interface design, then a screenshot of it running. Drag, scroll or use the arrows.

Interface design CopySure, 1 of 1
Screenshot CopySure running on Windows today

Free while we’re in preview

Get CopySure

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. here is exactly what to click. 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 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 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.

Questions about CopySure

What does CopySure do?

Dragging a folder onto a memory stick tells you it copied. It does not tell you the copy is right. CopySure reads every file back off the far end after writing it and checks the contents match the original, so a stick that is quietly failing or a cable that drops a byte gets caught rather than discovered years later. Files that are already there and already correct are left alone, so stopping a copy half way and starting it again costs you nothing.

Will CopySure delete my files?

It does not delete anything. Everything CopySure writes goes to the destination you name, so point it at a new folder if you would rather nothing already there was replaced.

Does CopySure send anything over the internet?

No. There is no network code compiled into CopySure at all, nothing in the binary can open a socket. 88 of the 100 programs here are like that.

Does CopySure run on a Mac?

Yes. There are builds for Apple Silicon and for Intel Macs, as well as for Windows and Linux, one file each, with no installer and nothing to uninstall.

Is CopySure free?

Yes, while Techlosoft is in preview: no account, no card, and nothing switched off. Later it is part of a plan covering all 100 programs rather than sold on its own, and anything you download now carries on working.

Reading on the job itself

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.

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