Help Fixing a Corrupt .FIT File

Hello, I'm trying to fix a corrupt .fit file. I have tried some of the online tools and can't figure our what is the error. I can see some of the data on my watch and looks like the number of laps is duplicated and no map is showing. Can anyone help fix the corrupt file?

2025-08-09-09-01-38.fit

  • Sorry. The file is way too small (25 kb) to have any meaningful data. No time stamps, not GPS data, and no device data. 

  • Thanks for checking. It's strange because the GPS was working during the activity (paces although seemed as expected) and on my watch I can go to the activity and see the distance/pace/heart rate and splits.

    I just tried another run and the same thing happened. Even tried an Elliptical and same issue (won't sync and get an error when trying to upload manually to Garmin Connect). The strength activity seems to be working though. 

  • This file is indeed missing a ton of key data, especially the "record" data, which represents your position, distance, speed, heart rate, cadence, etc., recorded at a rate of at most once per second.

    Without this key data, pretty much all you have is summary and lap data.

    However, you can still open the file in www.fitfileviewer.com and see:

    - your position at the end of every lap on a map

    - certain summary stats like the time and distance of your activity. e.g. I can see that you ran 15 km for 1 hour and 21 minutes (not including pauses)

    - time in hr zones for each lap

    - activity metrics like training effect, recovery time, etc.

    Even though fitfileviewer.com can technically fix your file, the result will still be rejected by connect because it's missing the meat and potatoes - the record data which says what you were doing at every point of the activity.

    I just tried another run and the same thing happened. Even tried an Elliptical and same issue (won't sync and get an error when trying to upload manually to Garmin Connect). The strength activity seems to be working though. 

    Could be that your device is running out of space. Which watch do you have?

    Try connecting your watch to a PC and manually deleting the older activities under \GARMIN\ACTIVITIES\. (You can copy them onto your PC before deleting them, although they should all be in Connect anyway. However, it costs you basically nothing to make your own copy of them.)

    Newer watches should be automatically deleting activities to conserve space though. Do you have a lot of maps or music on your device?

    If you have the map manager in your device (Settings > [System Settings / Watch Settings] > Map > Manager) it should say something like "X GB Available at the top of the screen. If this is the case, what does it say for you?

  • Thanks, I manually deleted the activities and that worked! It is a Forerunner 255S. I don't have music on it  (it's not the 255S music) and I don't have the map manager. I only have two courses saved on the watch but there are a lot of past workouts under the training. I've had it for over a year and haven't had to manually delete previously. I just hope it doesn't happen again with a race day or something.