Support

Your first transfer

Getting started with Seatbelt takes about ten seconds. Launch the app, drag a folder or a set of files onto the window, choose a destination, and press Transfer. Seatbelt copies every file, verifies it with a checksum, and shows you a clean summary when it’s done.

If anything goes wrong, like a read error, a permissions issue, a drive that disconnects mid-copy — Seatbelt will tell you exactly what happened and which files were affected. No silent failures.

Drag & drop workflow

Seatbelt is built around drag and drop. Drop files from Finder, from your desktop, or straight from a mounted camera card. You can drop multiple sources at once and Seatbelt will queue them in order.

Your most-used destinations are remembered automatically, so repeat jobs are just a drop and a click.

Supported formats

Seatbelt is format-agnostic — it transfers any file macOS can read. Camera RAW files (CR3, ARW, RAF, DNG), video rushes (MXF, BRAW, R3D, ProRes MOV), audio, documents, disk images — everything is treated the same way: copied and verified byte-for-byte.

Seatbelt also understands file sequences. A folder of numbered frames like IMG_0001.CR2 through IMG_0999.CR2 is recognised as a single logical group, making it easy to track large shoots at a glance.

Seatbelt vs Finder

Finder is heavily optimised by Apple and it’s fast. But it doesn’t verify what it copies, and when it runs into an error, it stops. If you’re not watching the screen at that moment, a stopped copy is easy to mistake for a finished one. On a busy offload on set, that can be a costly mistake.

Seatbelt is smarter. It verifies every single file using fast industry standard hashing, and gives you detailed, searchable logs for peace of mind. If a copy fails, you’ll know about it. And you’ll be able to quickly find the problem file or drive.

Stop & resume

Large transfers can take time, and sometimes you need to pause. Seatbelt supports stopping a transfer in progress and resuming it later. When you resume, it picks up exactly where it left off: files already verified are skipped, and only the remaining items are copied.

This works across app restarts and even across system reboots. Your transfer state is persisted to disk, so nothing is lost.

Duplicate detection

Seatbelt checks every file at the destination before copying.

If a file with the same name, size, and modification date already exists, it is treated as an exact match and skipped. This saves time and avoids unnecessary writes.

If a file with the same name exists but differs in size or modification date, it is treated as a modified file.

When a modified file is detected, Seatbelt lets you choose how to handle the difference. By default, modified files are overwritten, but this behavior can be changed to any of the following options:

• Overwrite
• Skip
• Rename (using default Finder renaming)
• Ask (each time)

Transfer logs

Every transfer produces a detailed log of which files were copied, where they went, how long it took, and whether verification passed. Logs are stored per-job and per-file, so you can audit any transfer after the fact.

Logs are accessible from the Transferlogs window, and a copy is created at your destination. From the Transferlogs window you can search and filter through many kinds of parameters, so you can detect even the smallest change, or find out if a specific file was transferred and when.

When using ASC MHL, You can also view the entire hash list history, so you can easily track prior generations of transfers.

PDF report export

Need a formal record of a transfer? Seatbelt can export a PDF report containing the full file manifest, checksums, source and destination paths, timestamps, and pass/fail status for each file as well as previews of destination image/video files.

This is especially useful for professional deliveries, client hand-offs, and archive documentation where a paper trail matters.

Generated Thumbnails

Supported video formats for thumbnails:

• H264, H265, Quicktime, Apple Prores, Red Raw, and Blackmagic Braw

Supported Image formats for thumbnails:

• Tif, JPEG, PNG, GIF and EXR

ASC MHL

Seatbelt is built around the industry standard ascmhl hash lists.

ascmhl creates a chain of custody by tracking every copy made from the original source media. It is commonly used in production workflows to safeguard media from capture through to archival.

This is especially useful when working with large datasets across multiple users and storage locations, where it helps prevent corrupted or altered files from being unknowingly propagated.

Seatbelt is validated against the current ASC MHL schema (v2.0).

Hashing algorithms

Seatbelt uses xxHash by default; an extremely fast, non-cryptographic hash that verifies file integrity without slowing down the transfer. For a typical camera offload, the verification overhead is barely noticeable.

xxHash is widely trusted in the media and data-management industry and catches even single-bit errors with near-perfect reliability.

For conformance to ASC MHL we also support md5, sha1 and c4.

Verification modes

Seatbelt offers three basic verification modes:

Source & Destination

Every file is hashed at the source, copied, then hashed again at the destination. If the two checksums match, the file is confirmed good. If they don’t, Seatbelt flags it immediately. This is the only mode that supports ASC MHL manifests.

Source Only

For managing multiple backups from a single source, we check the source against itself during and after transfer. If a drive is about to go bad, or read errors appear - you can catch it in time.

Transfer Only

Sometimes you just want a simple transfer. This mode compares file sizes and date stamps. Simple and fast.

Who is Seatbelt for?

Seatbelt is made for creators who move a lot of data. Filmmakers, editors, YouTubers, colorists, DITs. If you work with large files, shoot on cards, and juggle external drives, Seatbelt gives you the confidence that your files actually made it safely and cleanly.

Whether you’re offloading a camera card, copying media between SSDs, or archiving a finished cut, Seatbelt takes the guesswork out of the process.

Why macOS 26?

Seatbelt is built for macOS 26 and Apple’s current design, entirely in Swift. It isn’t a cross-platform app wearing a Mac costume: it uses the system’s own controls, looks and behaves like the rest of your Mac, and gets the latest improvements Apple ships to macOS.

Targeting the current version of macOS also means Seatbelt keeps pace with future releases, instead of being held back by older ones.

The flip side is that Seatbelt needs macOS 26 or newer, so please check your Mac before joining the beta or buying.

Pricing

$49 one-time at launch.

Call me old fashioned, but Seatbelt is a one-time purchase.

No subscription.

You get regular updates and support up to the next major version, and you’re backing an independent developer who actually uses the app every day.

Contact

I’d love your input on Seatbelt! For questions, feedback or press enquiries, email [email protected].

I make Seatbelt on my own, in my free time, but I aim to reply within a few working days.