Audio · exFAT recorder card
FLAC recording: recover after an interrupted recording
What can I do with losslessly compressed FLAC files after a recording interruption?
Short answer
Often most of the take plays: FLAC frames decode individually, so an interrupted file usually plays up to the last complete frame, even when STREAMINFO shows no total length or MD5. Copy the file first, decode the copy, and re-encode it to get a clean, finalized FLAC with the correct duration.
The situation
losslessly compressed FLAC files is missing, too short or unreadable after power loss, a card error or an unsafe stop.
The recording stopped in the middle and the file was never finalized, so it usually opens but reports no proper length. FLAC writes its frames continuously and fills in the total sample count and the MD5 in STREAMINFO only when a take ends in the normal way.
01 / Diagnose
Work out what actually disappeared
Each FLAC frame is self-contained and carries its own header and checksum, which is why an unfinished file still decodes up to the last complete frame. What is missing is the summary at the start: total samples remain zero, the MD5 stays empty, and seeking becomes unreliable. The audio up to the interruption is nevertheless present and verifiable frame by frame.
The payload may have been written before duration fields, indexes, directory entries or closing structures were committed. For FLAC recording, this matters because STREAMINFO, metadata and frame checksums allow strong validation
Check the last known path, trash and backups without writing to the original device.
02 / Protect the source
Preserve the best recovery chance
- 1
Switch the recorder off, remove the card and keep it out of use until the unfinished file has been secured.
- 2
Copy the file to a computer drive and treat the version on the card as the original you do not touch.
- 3
Decode the copy to WAV and listen to the end to hear exactly how far the recording got before it broke off.
- 4
Re-encode that decoded audio to a new FLAC file so the take gets a correct total length and a valid MD5.
Do not let a tagging or repair program write into the unfinished file on the card, and do not continue the session on the same card. Writing into a stream whose frame boundaries are unclear can destroy frames that still decode perfectly today.
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.
Finalizing an unfinished FLAC is an encoder task on a copy, not a scan of the card. File Recovery Hero reads exFAT cards and exports files from them, but it does not rewrite STREAMINFO, recalculate an MD5 or rebuild frames the interruption cut in half.
04 / Verify
Check the recovered content, not just its name
The re-encoded file should show a plausible duration, decode without a CRC error and end where the recording actually stopped. Listen to the final seconds: a short burst of noise before the end marks an incomplete last frame, which the re-encode should have dropped rather than kept.
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 exFAT recorder card be recovered in this situation?+
The recording stopped in the middle and the file was never finalized, so it usually opens but reports no proper length. FLAC writes its frames continuously and fills in the total sample count and the MD5 in STREAMINFO only when a take ends in the normal way. The result still depends on what remains readable on the source.
What should I avoid before scanning?+
Do not let a tagging or repair program write into the unfinished file on the card, and do not continue the session on the same card.
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?+
The re-encoded file should show a plausible duration, decode without a CRC error and end where the recording actually stopped.