Why is my 4K clip split into multiple files
Your card is formatted as FAT32, which can't store a single file larger than 4GB, so the camera splits one long take into numbered segments like C0001, C0002 (or 0001, 0002) — your footage is complete, and the segments rejoin into one clip in your editor as long as you keep the whole set together.
It's normal and nothing is lost. To avoid the split entirely, format your card as exFAT (no 4GB limit) if your camera supports it. When you offload, copy the whole card so the spanned set stays intact.
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Why one take becomes several files
Most camera cards ship formatted as FAT32, an older file system with one hard rule: no single file can be larger than 4GB. High-bitrate 4K, raw and ProRes footage hits 4GB in just a few minutes, so when a take crosses that boundary the camera can't keep writing to the same file — it automatically rolls over into a new one and keeps recording without dropping a frame.
That's why a single uninterrupted shot lands on the card as C0001.MP4, C0002.MP4, C0003.MP4 (Sony-style), or 0001, 0002 on other cameras. The numbers are the camera's way of saying "this is part 1, part 2, part 3 of the same continuous recording." Nothing crashed, nothing is corrupt, and no footage was lost between the parts — it's purely the 4GB cap doing its job.
What the FAT32 4GB limit actually is
The 4GB cap is a property of the FAT32 format itself, not your camera, your card's brand, or its total capacity. A 256GB FAT32 card can hold plenty of footage overall; it just can't put more than 4GB into any one file. So a 30-minute 4K take might span six or eight numbered segments even though the card is nowhere near full.
This is also why the split is consistent: it happens at almost exactly the same file size every time, because that's where FAT32 forces the rollover. It has nothing to do with battery, heat, or a fault on the card.
Do the segments rejoin in my editor?
Yes — in most professional editors, automatically. DaVinci Resolve, Premiere Pro and Final Cut Pro recognise the numbered segments as a single spanned clip and play them back seamlessly as one continuous take. You import the folder, and the editor stitches the parts together for you; you'll often see one clip on the timeline even though several files exist on disk.
The one condition: all the parts have to be present and kept together. If a segment is missing, renamed, or separated into a different folder, the editor can no longer recognise the set and may treat each piece as its own clip — or fail to join them at all. That's the whole reason to be careful at the offload stage.
The fix: copy the whole card, not just the files
Spanned clips only rejoin if the entire set stays intact. The safest habit is to copy the whole card — its full folder structure — rather than cherry-picking individual files. Copsy does exactly that: it copies the complete card to your drive (and optionally to Google Drive or Dropbox), preserving every numbered segment and the folder layout so your editor sees one continuous take. It also verifies every file with ASC-MHL checksums, so you know each part copied bit-for-bit.
How to merge spanned clips if you ever need to
Most of the time you don't need to merge anything — let the editor span them. But if a workflow requires a single physical file (for archiving or handing off), you can rejoin the parts after you've safely offloaded the originals:
- In the NLE: drop the spanned clip on the timeline (it's already joined) and export a single self-contained file.
- Concatenate the originals: command-line tools like FFmpeg can join same-codec segments into one file without re-encoding.
- Keep the originals: always merge from copies, never delete the numbered segments until your merged file is verified and backed up.
Merging is optional and vendor-neutral — the point is simply that you have the full, intact set to merge from.
How to avoid the split next time
If you'd rather have one continuous file straight off the card, format your card as exFAT when your camera supports it. exFAT has no 4GB per-file limit, so a long take records as a single file with no rollover. A few notes:
- Format in-camera, using the camera's own menu, not on the computer — that keeps the card structure exactly how the camera expects it.
- Check your camera's manual: some bodies and some card slots only support FAT32, in which case spanning is unavoidable (and harmless).
- exFAT doesn't change how you offload — you still copy the whole card and verify it. It just means fewer files per take.
Either way, your footage is fine. FAT32 spanning is a quirk to manage, not a problem to fix.
How Copsy keeps spanned clips intact
- Plug in the card. Copsy detects it by content and recognizes the camera/source.
- Copy the whole card. Every numbered segment and the full folder structure is preserved — to an external drive, plus optionally Google Drive or Dropbox in parallel.
- Verify every file. ASC-MHL checksums confirm each part — C0001, C0002, C0003 — copied bit-for-bit with nothing lost.
- Get pinged. A Telegram message tells you the card finished and verified, so your spanned set is complete before you reformat.
Frequently asked questions
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