How to repair corrupted RAW photos on Mac (CR2, NEF, ARW, RAF)

RAW photos are precious because they hold everything the sensor captured — but that richness makes them fragile. When a RAW file is pulled from a formatted SD card, a failing drive, or a card that was yanked mid-write, it often comes back as a file that Preview, Photos, or Lightroom refuses to open: a gray rectangle, a "file format not recognized" error, or a thumbnail that never resolves. The pixels are usually still in there. What's broken is the structure that tells software how to read them.

Most RAW formats — Canon CR2/CR3, Nikon NEF, Sony ARW, Fujifilm RAF, Panasonic RW2, Olympus ORF and others — are built on a TIFF-like container. A small header and a set of index structures (called IFDs, image file directories) point to where the thumbnail, the metadata, and the full-resolution sensor data live inside the file.

When a card is reformatted or a file is recovered from raw disk blocks, those headers and indexes can be damaged or partially overwritten even though the bulk of the image data survives intact. Software opens the file, can't find or trust the index, and gives up — so a mostly-complete photo reads as completely broken.

Repair rebuilds the structure around the surviving image data. DataRecover Pro identifies which RAW format the bytes belong to, then reconstructs the damaged parts: rewriting a valid header, rebuilding the IFD index that points to the main image, and restoring the EXIF metadata block so the camera model, dimensions, and orientation are read correctly again.

Because DataRecover Pro reads the EXIF "Make" tag, it can also label a generic recovered TIFF-style file with the correct camera-specific extension — turning an unidentified file back into a proper .nef, .arw, .orf, .rw2, or .raf that your editor recognizes on sight.

It works in three tiers. Clean repair fixes minor structural damage with no loss. Structural repair rebuilds the container around an intact sensor-data stream. When a file is only partly recoverable — say the card was overwritten halfway — partial repair salvages the readable portion, which for a RAW often still yields a usable, if cropped or lower-detail, image. A partial photo beats a gray rectangle.

Recover the files first if you haven't already — run a deep scan of the card or drive, which carves RAW files by their signatures even after a format. DataRecover Pro recognizes 47+ formats, including the major RAW variants.

During recovery, files that come back corrupted are routed through the repair engine automatically, so you receive a repaired file rather than a broken one. You can preview the result with thumbnails and Quick Look before saving, and the confidence score tells you whether a photo is a clean rebuild or a partial salvage. As always, save the repaired files to a different drive than the one you recovered from.

Repairing a corrupted file means parsing untrusted, malformed data — exactly the kind of input that can crash or exploit a careless parser. DataRecover Pro runs every repair in a locked-down worker process with no network access and no ability to write elsewhere on your filesystem, so even a deliberately malformed file can't compromise your Mac.

Most RAW corruption traces back to a few avoidable moments: ejecting a card before writes finish, shooting on a nearly-full or aging card, or copying with a flaky reader. Always eject cards properly, replace cards every few years, and offload to two places before formatting in-camera. And keep the originals backed up — repair is a rescue, not a backup strategy.