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Copying what's missing

Copy only the files that aren't backed up yet, to several drives at once, filed where they belong, with every copy verified.

Copy What's Missing copies the files that aren't backed up yet onto the drives you choose. It reads the card once, writes every drive from that one read, files each clip and photo into the folder it belongs in, and reads every copy back to check it before calling it done.

Arkeep only reads the card. It never deletes, moves or formats anything on it.

Start a copy

The Copy What's Missing panel appears in a card's result whenever files are missing and the card is still plugged in. See Checking a card.

  1. Check the folder name at the top of the panel, and change it if you like.
  2. Look over Where files go to see which folder each group of files goes into.
  3. Tick the drives to copy to.
  4. Click Copy to 2 Drives (the button names how many drives you ticked).

You can also press Shift-Command-C with the card selected, or press Return in the panel. For a simple card, you can copy right from the menu bar too. See Quick copy from the menu bar.

If you unplugged the card after the check, the panel says "Plug FX3 Card back in to copy from it." Copying needs the card itself.

Name the shoot folder

Everything from the card goes into one folder on each drive, which this guide calls the shoot folder. Arkeep suggests a name made from the card's name and today's date, for example "FX3 Card 10.28.26". Type over it with whatever you like, such as "Morgan & Ellis wedding".

You can also type a path, such as Clients/Bricks brand shoot/Day 1. As you type, Arkeep suggests folders that already exist on the drive, and tells you whether the name you've typed is an Existing folder or a New folder that's made when the copy starts.

If a new name is very close to an existing one, Arkeep asks "Did you mean…?" before anything is made, so a typo doesn't create a second folder for the same client. Pick the existing folder, or make the new one anyway.

If a folder with that name is already there, Arkeep asks what to do:

  • Add to It puts the new files in the existing folder. A file already there is never replaced.
  • Use a New Name adds a number to the name, for example "FX3 Card 10.28.26 2".

Choose where files go

Where files go shows one line for each group of files on the card: each file type, and each camera when the files say which camera made them. Each line says how many files there are, where they go inside the shoot folder, how much space they take and why Arkeep chose that folder. For example:

  • 312 MP4 files from your Sony A7 IV go into Footage/A Cam, because they're the "A cam on this card".
  • 24 WAV files go into Audio, because that's "where your .WAV files usually go".

Each line has a checkbox and a folder field:

  • Untick a line to leave those files on the card.
  • Type or browse to change the folder a line goes into.

Arkeep learns your layout

As Arkeep indexes your archive drives, it looks at how you already file your shoots: which folders your footage, audio and photos go into, which camera is usually your A cam and which file types you keep. The top of the section says where the plan comes from, for example "Learned from 214 shoots on your drives."

Until it has learned your layout, Arkeep uses a simple default: Footage, Audio and Photos. File types you don't usually keep start unticked, with a reason such as "you don't usually keep .thm files." Arkeep thinks in families of file types: RAW photos (ARW, CR3, NEF, RAF, DNG and the like), JPEG and HEIF photos, video, and audio. So a new camera's files are treated like the ones you already keep. For example, if you keep Sony .ARW files, a Canon card's .CR3 files are ticked and go where your .ARW files usually go. A type starts unticked only when you've never kept anything in its family. You can see the learned layout in Settings, under General, next to Offload layout.

Camera housekeeping files (XML sidecars, thumbnails and card databases) stay on the card.

Mirror the whole card

If you'd rather keep the card exactly as the camera wrote it, turn on Mirror the whole card in Settings, under General. Arkeep then copies everything on the card, in the card's own folders (PRIVATE, DCIM, XML sidecars and all), into the shoot folder.

Choose the drives

Your drives appear as large tiles, each with its name and free space. Archive drives say "Archive drive" under the name.

  • Default drives are already ticked. To choose them, open Settings, go to Archive Drives and tick Copy here by default for each drive you usually copy to.
  • Not enough space? A drive that can't fit the files is dimmed and says how much more space it needs.
  • Pick where on the drive. The folder link on each tile shows where the shoot folder goes on that drive, such as "Top level of the drive" or "/Clients". Click it to choose a different folder on that drive. Arkeep remembers the folder each drive was last copied into.

A line under the tiles tells you how many copies you'll have when it's done, for example "1,214 files will be on 2 drives." If you tick only one drive, the line turns amber: "A second drive keeps a backup if one fails."

To work from the keyboard, press Tab to move into the tiles, use the left and right arrow keys to move between them, and press Space to tick or untick one.

Copying to several drives at once

One click starts every drive you ticked. Arkeep reads each file from the card once and writes it to every drive from that single read, so a second or third drive adds little time, especially when each drive has its own connection to your Mac.

While the copy runs, the card's page shows:

  • each drive with its own progress bar and file count;
  • the time left;
  • live speeds for reading the card and writing the drives, and which one is the slower part;
  • Pause, Resume and Stop. Stop keeps every file already copied and verified.
A copy in progress in Arkeep, showing progress for each destination drive and a speed line with the card's read speed, the drives' write speed and a note saying which part is slower
A copy in progress, with the live read and write speeds.

If a copy feels slow, the speed line tells you why. See Troubleshooting.

Background indexing and fingerprinting pause while a copy runs, so they don't slow it down. They carry on afterward.

How every copy is verified

By default, every copy is checked by its contents, not only by its name and size:

  1. As Arkeep reads each file from the card, it works out a checksum (XXH3-128) of the whole file.
  2. It writes the copy to each drive under a hidden temporary name.
  3. It reads the copy back from the drive itself and works out its checksum again.
  4. Only when the two match does the copy get its real name.

A file is done only when every drive's copy matches. Files Arkeep copied and verified count as backed up right away, and they're added to that drive's file list in Arkeep.

Proof of the offload

After each copy, Arkeep writes two files into the shoot folder on every drive:

  • An ASC MHL checksum list in an ascmhl folder. This is the film industry's standard format, so a client or post house that asks for proof of a clean offload can check it with their own tools.
  • A short PDF, named after the shoot folder, for example "Morgan & Ellis wedding Offload Report.pdf". It lists the card, the cameras, every drive and how each copy went.

Fast copy

If you'd rather have speed than certainty, turn on Fast copy in Settings, under General. Arkeep then skips reading each copy back. Those copies are labeled "copied, not verified" in amber, and they never count as backed up. The copy panel reminds you when Fast copy is on.

When the copy finishes

You get a notification, for example "FX3 Card: copied to 2 drives" with "1,214 files, every copy verified."

The card's page then shows how the copy went on each drive:

  • Green: "Passed: all 1,214 files verified."
  • Amber: "Copied, not verified (Fast copy)."
  • Red: for example "3 failed, 1,211 copied." Click Retry Failed to try those files again.

Each drive has a Show in Finder button. Open Files to see every file on every drive with its result. If any file got a new name because a different file already had its name, Arkeep lists it under "saved under a new name."

Arkeep then checks the card again on its own, so its result shows what's backed up now.

Safety rules

  • Arkeep never writes to the card. It never deletes, moves or formats anything on it.
  • Arkeep never overwrites a file. If a different file already has the same name, the copy is saved with a number added, for example C0001 (2).MP4. This works on exFAT drives as well as APFS and Mac OS Extended.
  • Arkeep doesn't copy a file twice. If the same file, with the same contents, is already in place from an earlier copy, it's marked "already there, same contents" and nothing is written.

If a copy is interrupted

A drive is unplugged

If you unplug one drive in the middle of a copy, only that drive stops. Its row says "Unplugged. Plug it back in and the copy picks up where it stopped." The other drives carry on. When they're done, Arkeep sends a notification saying which drive it's waiting for. Plug it back in, along with the card, and the copy finishes.

You quit Arkeep

If you quit while a copy is running, Arkeep asks first. Files already copied and verified are kept.

Arkeep or your Mac stops unexpectedly

If Arkeep quits or crashes in the middle of a copy, the next time it opens it shows Copy was interrupted on the Overview page and on the card's page, along with a notification. It tells you how many files were already copied and verified.

  1. Plug in the card and the drives you were copying to.
  2. Click Resume. Arkeep skips the files already copied and verified and copies the rest.

Click Dismiss if you'd rather not finish it. Files already copied stay where they are.

Before resuming, Arkeep removes its own unfinished hidden files from the shoot folder (names that end in .arkeep-partial). It never removes anything else. See Troubleshooting for more on what to do after a crash.