Photos & RAW · camera RAW candidate
RAW preview is visible but the original will not develop
Does an embedded RAW preview prove the RAW file is intact?
Short answer
No. Many RAW files carry a small embedded JPEG preview that can survive while the sensor data behind it is missing or cut off. A thumbnail in Finder, Explorer or a recovery list therefore proves little. Treat the file as intact only when your RAW converter develops it at full resolution and reads its metadata.
The situation
Finder, Explorer, or a recovery app shows a thumbnail, but the RAW converter fails.
The thumbnail comes from a small JPEG stored inside the RAW file, usually near its beginning. It is a few hundred kilobytes next to many megabytes of sensor data, so it survives situations that already cost the real image, and it proves nothing about the rest.
01 / Diagnose
Work out what actually disappeared
File managers and recovery lists display that embedded preview because it is cheap to read. The sensor data lies behind it and makes up nearly the whole file, so any truncation or reused block hits the payload long before it touches the preview. A converter that refuses to develop the file is reporting a payload problem, not a display problem.
Many RAW files contain a small embedded JPEG that can survive separately from sensor data.
Check the last known path, trash and backups without writing to the original device.
02 / Protect the source
Preserve the best recovery chance
- 1
Treat every candidate as unconfirmed until a RAW converter has developed it, however convincing the list preview looks.
- 2
Compare file sizes within the shoot: frames from one body and setting stay in a narrow range, and small ones are suspect.
- 3
Go back to the source medium while it is unchanged and rescan it read-only for the RAW format of that camera.
- 4
Export the new candidates to a separate drive and develop them before deciding which copy of each frame to keep.
Do not extract the preview and treat it as the rescued photograph, and do not overwrite the RAW file with it. The preview is heavily reduced and carries none of the editing latitude the original had. Nothing should be written back to the source medium either.
03 / Choose the method
Match the tool to the source
For stable, readable exFAT, NTFS and FAT16/FAT32 or uncompressed IMG, DD, RAW and BIN images.
Unconfirmed exports are marked .UNVERIFIED.
File Recovery Hero recovers whole RAW files from readable exFAT, NTFS and FAT16/FAT32 media in a read-only pass; it does not repair a RAW whose sensor data was overwritten and cannot turn an embedded preview into a full image. Failing media is a laboratory case.
04 / Verify
Check the recovered content, not just its name
A RAW file is intact when the converter opens it at the sensor dimensions of the camera, reads aperture, shutter and lens metadata, and lets you move exposure and white balance as usual. A file that yields nothing but its preview there is a fragment, however sharp the thumbnail looked.
Keep the source until two verified copies exist. One working preview is not enough.
Sources and technical references
FAQ
Questions about this recovery case
Can camera RAW candidate be recovered in this situation?+
The thumbnail comes from a small JPEG stored inside the RAW file, usually near its beginning. It is a few hundred kilobytes next to many megabytes of sensor data, so it survives situations that already cost the real image, and it proves nothing about the rest. The result still depends on what remains readable on the source.
What should I avoid before scanning?+
Do not extract the preview and treat it as the rescued photograph, and do not overwrite the RAW file with it.
Does scanning write to my memory card?+
Your memory card is only read. Nothing is saved to it.
How do I know whether the result is complete?+
A RAW file is intact when the converter opens it at the sensor dimensions of the camera, reads aperture, shutter and lens metadata, and lets you move exposure and white balance as usual.