Make two verified copies before you reuse the card.
Free, offline camera-card offload for macOS and Windows.
Download ProofCat 0.3.0
· Technical documentation
You finish a shoot. ProofCat copies the card to your chosen drives, checks those copies independently, and gives a clear answer. It never formats anything for you. It tells you when the evidence is strong enough to reuse the card — and when it is not.
- Choose the camera card and two destination drives.
- ProofCat copies and checks every required file.
- Reuse the card only when the app says SAFE TO FORMAT.
Any missing file, failed check, interrupted job, full drive, or ambiguous setup withholds that verdict. Two folders on the same physical disk do not count as two backups.
- Offline by default. Your media stays on the machine.
- Two real destinations. ProofCat checks devices, not just folder names.
- Resume instead of guessing. Reconnect a drive and continue a stopped job.
- Evidence you can hand over. Keep a readable report with the copies.
- More than offload. Inspect media and export metadata and delivery reports in the same app.
ProofCat 0.3.0 runs on macOS Apple Silicon and Windows x64. Download the installer for your platform from the release page.
macOS may show a Gatekeeper prompt and Windows may show a SmartScreen prompt on first launch because the current release is not Apple-notarized or Authenticode-signed. The release page includes checksums and signatures; the technical documentation explains how to verify them.
The product deliberately keeps its simple promise separate from the engineering evidence behind it.
| Question | Read |
|---|---|
What exactly does SAFE TO FORMAT mean? |
Safety contract |
| How does the copy and verification pipeline work? | Technical documentation |
| What happened on real hardware? | Hardware test report |
| What are the limits and threat boundaries? | Threat model |
| How does ProofCat compare with established tools? | Honest comparison |
| How can I build or contribute? | Contributing |
ProofCat is MIT-licensed. The source is public because a tool that tells you whether a shoot card may be reused should be inspectable. If you find an issue, open a GitHub issue. For a security issue, use private vulnerability reporting.