How to offload footage from a camera card on a Mac

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The one rule: your footage must never live in only one place

On a shoot, the most dangerous moment is the few minutes between when you pull a card and when a verified backup exists. The card could be lost, corrupted, or accidentally formatted, and an entire scene is gone, unrecoverable. Everything below exists to shrink that window to zero.

The framework professionals borrow from data backup is 3-2-1: keep three copies of your footage, on two different types of media, with at least one copy off the set. On a normal day that means the original card, a working drive, and a backup drive or a cloud copy. The exact number matters less than the habit: always have redundancy before the card gets wiped.

The safe offload workflow, step by step

1. Treat the card as a read-only original

Pull the card and put it in a card reader rather than offloading from the camera over USB. Readers are faster and free up the camera. If the card has a physical write-lock tab, flip it. Until both copies are verified, don't rename, move, or delete anything on the card. It is your only original.

2. Copy the whole card to at least two destinations

Copy the entire card with its folder structure intact, not just the clips you think you need. Camera file systems store sidecar, metadata, and spanned-clip files alongside the video, and cherry-picking breaks them. Send that copy to a working drive and a second backup. Copying to both at once (in parallel) is faster and means there's never a stretch where only one copy exists.

3. Verify every file with checksums (the step people skip)

This is where most offloads quietly go wrong. A copy that finishes is not the same as a copy that is correct. Card readers, cables, hubs, and drives can silently drop or alter bytes, and Finder won't warn you. A checksum is a short fingerprint calculated from each source file and re-checked on the destination. If they match, that file copied bit-for-bit with nothing lost.

The film-set and Netflix-delivery standard for this is ASC-MHL (Media Hash List), which records a checksum for every file plus a manifest you can re-verify later. Other valid checksum types are xxHash and MD5. If your tool can't tell you "every file verified," you aren't actually backed up. You're guessing.

4. Organize by date and source

Drop the footage into a predictable structure, typically by shoot date, then by camera or card source (e.g. 2026-06-20 / A-CAM / A001). Good organization makes the footage findable in post and, just as importantly, prevents a second offload from overwriting the first when two cards share the same auto-generated folder names.

5. Only now — format the card, in the camera

Do not reformat or reuse a card until you have two verified copies and you've spot-checked that a clip or two actually plays back. When you're sure, format the card in the camera that shot it, not in the Mac Finder. Camera formatting lays down the file system the camera expects and avoids the subtle corruption that Finder "erase" can introduce.

Why "just drag it in Finder" is risky

Dragging a card to a drive in Finder feels like a backup, but it has three quiet failure modes: there's no verification (a dropped or corrupted file looks identical to a good one), it's easy to copy only part of the card or the wrong folders, and there's no log proving what happened. People discover the problem days later in the edit, long after the card was formatted. Use a tool that verifies, and keep the Finder drag as a last resort.

Tools that do this — free and paid

Plenty of apps handle verified offload. Here's an honest, dated snapshot of the common ones on Mac and where each fits.

Pricing and features change — figures above were last verified in June 2026. OffShoot is the rebranded Hedge; ShotPut Pro adds an annual update plan on top of its perpetual license. Other options worth knowing: DaVinci Resolve's free Clone Tool (xxHash, no auto-detect or cloud), the free verify-only MhlFileVerify, Terminal shasum, and higher-end DIT software like Pomfort Silverstack (~$300–$600/yr). Check each vendor's site for current details.

How Copsy automates the whole workflow

Copsy, a free Mac camera-offload app, does every step above without you babysitting it:

1. Plug in the card. Copsy detects it by content and recognizes the camera/source (Sony, ARRI, Blackmagic, RED, Canon, drones, audio recorders).
2. Pick destinations. An external drive, plus optionally Google Drive or Dropbox, copied in parallel, so the second copy gets made right away.
3. Walk away. Copsy copies, organizes by date and source, and verifies every file with ASC-MHL checksums.
4. Get pinged. A Telegram message tells you it finished and verified, so you know it's safe to format the card.

It's free, with no card limit and no signup, on macOS 13 or later.

Frequently asked questions