Install on Windows

“Windows protected your PC” — what it means

Microsoft Defender SmartScreen shows this blue dialog for any program that is not code-signed with a paid certificate and has not yet built download “reputation”. It is a statement about popularity and signatures, not about what the program does. blitcp is not signed because code-signing certificates cost several hundred euros per year — hard to justify for a free, open-source tool whose every line of source is public and whose binaries are built from that source with PyInstaller.

To proceed past the dialog:

1. Click More info (small link under the text).
2. Click Run anyway.

This is needed once per downloaded file. But don't take the dialog's word — or ours — for it: verify the file cryptographically instead. It takes ten seconds.

Verify your download (SHA-256)

In PowerShell, in your Downloads folder:

Get-FileHash .\blitcp-windows.exe -Algorithm SHA256

Compare the output against the official digest below. These hashes are computed by GitHub itself when each binary is uploaded to the release — the same values are shown via the GitHub API for the release. If the hash matches, the file on your disk is byte-for-byte the file from the release; if it doesn't, delete it and re-download from GitHub only.

Official SHA-256 digests — v4.0.0

Antivirus false positives

PyInstaller-packaged Python programs are occasionally flagged by antivirus heuristics simply because of how they bundle the interpreter — it is a known false-positive pattern that affects many open-source Python tools. If your AV quarantines a file whose SHA-256 matches the official digest above, the file is exactly what was released; you can inspect the source it was built from or build it yourself with build.py.

First run

.\blitcp-windows.exe "C:\Projects\my-app" "E:\Backup\my-app"

That's it — no installation step. See the local copies guide for more examples (long paths, ReFS block cloning and NTFS hardlink dedup are handled automatically), or the full CLI reference.