# VerifiedCopy

> VerifiedCopy is a $4.99 macOS app that copies files and proves each copy is intact. Every chunk is written, flushed to the drive, read back, and its SHA-256 hash compared with the source. If a chunk doesn't match, only that chunk is rewritten and re-checked, so a bad block never means restarting the file or the copy. Made by independent developer Ting Tze Chuen.

Last updated: 2026-10-07

Full text of the homepage and all guides in one file: [llms-full.txt](https://verifiedcopy.app/llms-full.txt)

## Key facts

- Platform: macOS 14.0 or later; universal app for Apple silicon and Intel Macs; native Swift; 1.8 MB on the Mac App Store
- Price: $4.99 one-time on the Mac App Store, no subscription; 14-day free trial via DMG
- Version: 1.2.0 (released 2026-10-20); first released 2026-04-13
- Privacy: sandboxed, fully offline (no network access), no data collection, no accounts
- Copy & Verify: 1 to 3 destinations in one pass; the source is read once
- Verify & Repair: scans an existing backup against a known-good source and rewrites only damaged chunks
- Integrity view: block map of intact, corrupted, and repaired chunks
- Reports: copy jobs can save a CSV or JSON report to each destination (JSON includes per-chunk SHA-256 hashes); Verify & Repair scans can save a hash manifest (.verifiedcopy-manifest.json)
- Integrations: Finder Services ("Copy with VerifiedCopy"), Dock drop, Shortcuts and Spotlight actions, menu bar status, URL scheme
- Options: auto-dated destination folders, conflict pre-scan, remembered destinations, eject after copy, 1 to 4 parallel copies

## How verification and repair work

1. Each file is processed in chunks of 1, 4, 8, or 16 MB (default 4 MB).
2. Each chunk is written to the destination and flushed to the drive with F_FULLFSYNC.
3. The chunk is read back and its SHA-256 hash is compared with the source chunk.
4. A mismatched chunk alone is rewritten and re-checked, up to 3 attempts by default (configurable 1 to 10). The rest of the file is untouched, so a bad block costs one chunk's rewrite instead of recopying a multi-gigabyte file.
5. By default, a full-file SHA-256 pass runs afterwards as a final check.

Verify & Repair applies the same idea to backups you already have: it compares the backup with the original chunk by chunk, rewrites only the damaged chunks, and re-verifies the repaired chunks by default.

## Compared with Finder, cp, and rsync

- Finder: copies but never reads the copy back to verify it
- cp: no verification
- rsync: checksums only if you re-run it with -c; re-sends whole files and can't show which part is damaged
- VerifiedCopy: read-back SHA-256 verification on every chunk by default, repairs only the bad chunk, up to 3 destinations in one pass, native Mac interface

## Pricing

- $4.99 USD one-time purchase: [Mac App Store](https://apps.apple.com/app/verifiedcopy/id6761552532)
- 14-day free trial: [VerifiedCopy-1.2.0.dmg](https://github.com/300apm/VerifiedCopy-releases/releases/download/v1.2.0/VerifiedCopy-1.2.0.dmg)

## Requirements

- macOS 14.0 (Sonoma) or later, on Apple silicon or Intel Macs
- Works with any drive macOS can mount: external SSDs and HDDs, USB sticks, SD and camera cards, network shares, exFAT drives

## Pages

- [Home](https://verifiedcopy.app/): what VerifiedCopy does, features, comparison table, specs, FAQ
- [How to verify a file copy on Mac](https://verifiedcopy.app/verify-file-copy-mac/): shasum, cmp, diff -rq, shasum -c, rsync -c, and automatic verification compared
- [exFAT file corruption on Mac](https://verifiedcopy.app/exfat-corruption-mac/): why exFAT corrupts silently (no journal, no data checksums), repairing with First Aid, prevention
- [How to safely offload camera cards on a Mac](https://verifiedcopy.app/offload-camera-cards-mac/): two drives, checksum verification, format in camera
- [Finder error -36, -43 and -50 on Mac: what they mean and how to fix them](https://verifiedcopy.app/finder-error-36-43-50-mac/): what Finder copy errors -36 (I/O), -43 (file not found) and -50 (bad parameter) mean and how to fix them
- [How to tell if a file is corrupted on a Mac](https://verifiedcopy.app/check-file-corrupted-mac/): signs of corruption by file type, checks that work without the original, and hash comparison against a known-good copy
- [“Too large for the volume’s format” on Mac: how to copy files over 4 GB](https://verifiedcopy.app/file-too-large-fat32-mac/): the FAT32 4 GB file limit, checking a drive's format, reformatting to exFAT or APFS, and splitting files
- [Does APFS protect your files from bit rot?](https://verifiedcopy.app/apfs-bit-rot-mac/): what APFS checksums (metadata) vs not (file data), ZFS/Btrfs comparison, and practical protection against silent corruption
- [Do Time Machine and Carbon Copy Cloner verify your backups?](https://verifiedcopy.app/does-time-machine-verify-backups/): what Time Machine Verify Backups, tmutil verifychecksums and Carbon Copy Cloner's checks actually verify
- [OffShoot vs ShotPut Pro vs VerifiedCopy: Mac offload tools compared](https://verifiedcopy.app/offshoot-shotput-pro-verifiedcopy-comparison/): honest comparison of OffShoot, ShotPut Pro, Pomfort Offload Manager and VerifiedCopy
- [Privacy policy](https://verifiedcopy.app/privacy-policy/): no data collection

## FAQ

- Does Finder verify copied files? No. Finder reports a copy as done once the data is written and never reads it back.
- How does VerifiedCopy verify a copy? Each chunk is written, flushed with F_FULLFSYNC, read back, and its SHA-256 compared with the source; a full-file SHA-256 pass follows by default.
- What happens if a chunk is corrupted? Only that chunk is rewritten and re-checked (up to 3 attempts by default), not the whole file or job.
- Can it repair an existing backup? Yes. Verify & Repair rewrites only the damaged chunks of a backup, using a known-good source.
- Can it copy to several drives at once? Yes, up to 3 destinations in one pass, reading the source once.
- Does it help with exFAT corruption? Yes. It reads each copy back from the exFAT drive and compares hashes before you hand the drive over.
- Does it send data anywhere? No. It is sandboxed, has no network access, and collects no data.
- How much does it cost? $4.99 once on the Mac App Store, with a 14-day free trial.

## Contact

- Author: Ting Tze Chuen, independent macOS developer, [ting.rocks](https://ting.rocks)
- Email: hello@ting.rocks