Did Zwift change fit file structure? cannot upload into Garmin Connect


I cannot seem to get Zwift Activity .fit files into Garmin Connect as of 12/21. I have been using the automatic upload since that feature rolled out, but this seemed to fail on last nights’ ride from 12/21/17, so I tried to manually upload the .fit file today. This was met with the “unable to upload” error as if the file is corrupted. Downloading a new .fit file from the My Zwift page, using different browsers, clearing cookies, logging in, out and disconnecting the link from Zwift from GC and reconnecting seems not to have helped. 

Perhaps the problem lies on the garmin side of things, but its acting like the files from zwift have changed somehow as other activities are syncing 100% correctly…any Ideas?


Hi Ryan,

Have you checked to see if the .fit files upload on other sites? You might also be able to try fixing the .fit files at fitfiletools.com.

Hi Josie,

Over the last few days it seemed to have fixed itself but today the problem occurred again, but the flip side I think I have isolated the problem.

Files have only failed to upload on Workout rides after I had discovered/used the skip block function. Completing a full workout or even ending a workout early but not skipping a middle block seems to allow the upload to work (auto or manually). Perhaps it is something with an empty lap field or null value for a “lap” in that fit file that doesn’t allow it to go into GC. Easy enough to avoid and maybe encourages me not to skip. Perhaps that is something you all could address with your file structure so it won’t conflict with garmin (or for garmin I suppose).

Of note, the problem occurs with rides >30 min and several simulated miles, so it wasn’t a problem with the ride being too short… I understand that small rides (<5km) are not synced by design. 

Otherwise, to answer your question. I was able to upload the fit to other sites. I made a Strava acct and the file could upload there. Interestingly, putting the “broken” fit file into Strava and then exporting from strava in gpx format allows the ride to be put into GC.