FIT Rescue repair a corrupt or rejected Garmin FIT file

How to repair a Garmin FIT file

1. Open the file

   Drop the .fit file here or choose it. It is read by this page, on your device: nothing is uploaded.

2. Read the diagnosis

   Each problem is explained in plain words, with its severity and whether Garmin Connect is likely to refuse the file.

3. Choose the repairs

   Every repair shows what it changes and what is lost, with a before and after view. You can undo any of them.

4. Download

   Get the repaired FIT file, checked by reading it back, or export GPX, TCX, CSV and a report of the diagnosis.

What FIT Rescue detects and repairs

• File cut short

  The watch or the transfer stopped in the middle of a record. The incomplete end is removed and the file is closed properly.

• Header, size or checksum errors

  A damaged header, a wrong data size or a wrong CRC checksum. They are rebuilt from the readable data.

• Unreadable bytes

  A damaged block in the middle of the file. Reading resumes at the next valid message and the block is skipped.

• Watch crashed before saving

  No session or activity summary. The last lap, the session and the activity are rebuilt from the recorded points.

• Impossible or backwards times

  Points dated 1990 or 2099, or going back in time. They are removed so the timeline is in order.

• Holes in the recording

  A long gap with no pause. It is marked as a pause, so the moving time is no longer inflated.

• GPS errors

  Points at 0°, 0° (off the coast of Africa), outside the globe, or jumps across the map. Only the position is cleared.

• Heart rate and power spikes

  Values such as 250 bpm or 4,000 W. They are cleared and averages and maxima are recalculated.

• Wrong sport

  A ride saved as a run, for example. You pick the right sport for the laps and the session.

Why Garmin Connect rejects a FIT file

Garmin Connect, Strava and other apps check a FIT file before importing it. A file whose size does not match its header, whose checksum is wrong, or that ends in the middle of a message is usually refused with a generic upload error.

A file can also be readable but incomplete: when a watch runs out of battery or freezes, the session summary is never written. Some apps then refuse the activity, others show it without distance or duration.

FIT Rescue tells you which of these cases applies to your file. It never announces a repair it has not checked: every repaired file is read back, its checksum is verified, and the result is shown before you download it.

Private by design

The file is read with JavaScript in this page. It is not sent to a server, not stored, and no account is needed. You can even load the page, switch to airplane mode and repair your file.

What it cannot repair

• A file that is not a FIT file at all (for example a GPX or a file full of zeros), or one with no readable message.
• A file whose clock was wrong for the whole activity: the real date cannot be guessed.
• Data that was never recorded: lost bytes cannot be recreated. FIT Rescue keeps everything that can still be read and lets you export it.

Garmin FIT file questions