A few months ago my Garmin Edge 810 froze, whcih meant I had to force shut it down whilst it was still recording a ride. Luckily, the files had been saved to the Garmins memory so I could access them through my PC, and pull them out. However, when I tried to upload it to Strava, it threw up an error that the files were corrupted, which I expected.

After searching around a little, I found this site: https://www.fitfiletools.com/#/top that allowed me to upload my FIT file, and fix it. I used the Corrupt Time Fixer, and this solved the corrupted file and meant that it could be uploaded to Strava and Garmin Connect.

Hopefully no one will be unlucky enough to encounter this issue, however if you do the website should be able to sort it out for you.