VerifiedCopy is a $4.99 Mac app that copies your files to up to three drives, reads every copy back, and checks it against the original with SHA-256. Finder never does that: it calls a copy done the moment the last byte is written.
A copy isn't trusted just because it was written. It has to be read back from the drive and matched against the source.
Your files stream to one, two, or three drives at once, with progress for each file and the whole job.
Each block is pushed all the way out to the drive, then read back from the copy. Nothing counts as done just because it was written.
Each block's SHA-256 hash is checked against the source. If one block is off, only that block is rewritten and checked again. No starting the whole copy over.
Pick your files, watch them get checked, and see exactly what's healthy. No mystery progress bar that only tells you what macOS believes.
Ting Tze Chuen, maker of VerifiedCopyI kept copying videos to an exFAT drive, ejecting safely, and finding them corrupted on the TV.
macOS said the copy succeeded. Safe eject said the drive was safe. Neither actually reads the file back to confirm the bytes survived the trip. VerifiedCopy is the tool I wanted to exist: it copies, then re-reads every byte and tells you honestly whether the copy arrived intact.
Six things it does well. That's the whole app, and every feature is there to make sure your files arrive exactly as they left.
Copy to one drive or several, read every byte back, and confirm it matches. A bad block gets rewritten on the spot, so you never restart the copy.
Rewrites only the damaged blocks, not the whole file. Big archives stay quick to fix when just a few sectors go bad.
A block map for any file. Healthy, damaged, and repaired parts are easy to see at a glance.
One copy job, up to three destinations. A verified 3-2-1 backup across several drives in a single pass.
No network, no analytics, no accounts. It runs in Apple's macOS sandbox and only touches the files you pick.
A native Swift app under 2 MB. Works from the app window, Finder Services, the Dock, Shortcuts, and Spotlight.
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Silent corruption on exFAT is a longstanding macOS issue. Finder will happily report a copy as successful even when bytes got mangled on the way, especially with large files or drives shared between Mac and Windows. VerifiedCopy reads every copy back from the exFAT drive and compares it byte-for-byte with the original, so you catch problems before you hand the drive off, not after someone opens it on Windows. Why exFAT corrupts files on Mac
Finder, cp, and a plain rsync all say "done" once the last byte is written. Only one of these reads the copy back and proves it matches.
| What it does | Finder | cp | rsync | VerifiedCopy |
|---|---|---|---|---|
| Reads the copy back after writing | No | No | Only if you re-run with -c | Yes, every file, by default |
| Checksum | None | None | Whole-file, on re-run | SHA-256 per 1–16 MB chunk |
| Pinpoints where a file is damaged | No | No | No | Yes, block map |
| Repairs only the damaged part | No | No | Re-copies the file | Rewrites only bad chunks |
| Several destinations in one pass | No | No | No | Up to three |
| Verification record | None | None | Terminal output | CSV/JSON report with per-chunk hashes |
| Interface | Finder | Terminal | Terminal | Native Mac app |
Swipe the table sideways to see every column.
Short, plain answers. If something's missing, just ask.
Every file is copied, then read back from the destination drive and hashed with SHA-256 in chunks of 1 to 16 MB (4 MB by default). Each chunk's hash is compared against the source. If a chunk doesn't match, only that chunk is rewritten from the source and checked again, so one bad block never means restarting a big copy. A full-file SHA-256 check then runs by default.
Finder can't do it: it never reads the copy back. You can compare checksums by hand in Terminal (for example with shasum -a 256 on both files), or use VerifiedCopy, which copies the files, re-reads every copy from the destination, and compares SHA-256 hashes automatically for every file in the job. See all the ways to do it.
Finder copies files but doesn't verify them afterwards. A damaged sector, flaky cable, or failing drive can silently corrupt a file during the copy and you'd never know. VerifiedCopy re-reads every copy and confirms it matches the original.
Yes. VerifiedCopy works with any drive macOS can mount, including external SSDs, HDDs, USB sticks, SD cards, and network shares. You can copy to up to three destinations in one pass.
Yes. This is one of the most common reasons people install VerifiedCopy. Silent file corruption on exFAT drives is a longstanding macOS issue, especially with large files or drives shared between Mac and Windows. VerifiedCopy reads every copy back from the exFAT destination and compares it byte-for-byte against the source, so you know the file is intact before you hand the drive to a Windows machine.
Silent data corruption (sometimes called bit rot) is when a file's contents change without any error message, caused by aging storage, faulty cables, or stray cosmic rays flipping bits. You often only notice when you try to open the file years later.
No. VerifiedCopy runs fully offline inside Apple's macOS sandbox. It makes no network requests, uses no analytics, and only accesses files you explicitly select.
Yes. Verify & Repair scans an existing backup against a known-good source and rewrites only the damaged chunks, not the entire file. That keeps repair fast, even for large archives where just a few sectors have gone bad.
Any file, any size. VerifiedCopy verifies raw bytes rather than looking at file formats, so it works equally well for photos, videos, databases, archives, or any other type of file.
cp doesn't verify copies at all. rsync's -c flag compares checksums, but only if you re-run it yourself in Terminal, and it can't pinpoint or repair just the damaged region. VerifiedCopy is a native Mac app with SHA-256 verification on by default, a visual progress view, up to three destinations in one pass, and a block-level repair mode.
VerifiedCopy costs $4.99 as a one-time purchase on the Mac App Store. There is no subscription. A free 14-day trial is available as a direct download.
VerifiedCopy requires macOS 14 Sonoma or later and runs natively on Apple silicon and Intel Macs. It is a native Swift app under 2 MB.
Practical how-tos for checking copies, fixing drive errors and corruption, and choosing the right tools, whether or not you use VerifiedCopy.
Five ways to prove a copy matches the original, from shasum in Terminal to automatic SHA-256 checks.
Why exFAT drives corrupt files silently, how to repair them, and how to stop it happening again.
Read the guideTwo drives, checksums on every file, and only then format the card in camera.
Read the guideWhat each copy error means, what causes it on external drives and SD cards, and the fixes that work.
Read the guideSigns of a damaged photo, video, archive or PDF, Terminal checks without the original, and the one test that proves it.
Read the guideWhy a FAT32 drive refuses big files, how to check the format, and how to reformat or split safely.
Read the guideWhat APFS checksums and what it doesn't, how ZFS differs, and how to protect files that matter.
Read the guideWhat Time Machine's Verify Backups, tmutil and Carbon Copy Cloner actually check, and how to run each.
Read the guideAn honest side-by-side of Mac offload tools: prices, checksums, MHL, platforms, and who each is for.
Read the guide$4.99, one-time purchase. No subscription. 14-day free trial. Runs on macOS 14 Sonoma and later.
