Zwift generates corrupt fit files

The fit files that get saved in Documents/Zwift/Activities/ are always corrupt if I don’t upload at the end of a ride through Zwift. I cannot later import them into Garmin connect. The only file that seems to work (but cuts off some of the end of the ride) is the file. This was not always the case - the bug seems to have crept in around the time Makuri Islands was released.

To reproduce the error: End a ride and pick the trash can icon. The most recent fit file in Documents/Zwift/Activities/ will not upload to Garmin.

Every activity I do on Zwift, I go to my activity feed on ZwiftDotcom website, hit the little gear icon and download the FIT file to a folder on my computer. Then open GC and import. Never doesn’t work. Never knew about the folder you’re referring to.

Hi @Mathew_Bittleston
You want to pull FIT files that are uploaded to the server, not the one on your local hard drive.

Please follow these step by step instructions. Would you let us know if that works for you?

Hmm… Actually, he wants to use the one on his machine.

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@shooj No I don’t want to add the extra steps of downloading the files from the server. That’s a pain and completely unnecessary: Why is it creating a corrupt file on my computer? Seems the file is being made on the computer in the first place, then something is messing it up right at the end.

Presumably it is not messing it up on purpose but rather just not bothering to write into the end of the file whatever is needed to terminate the data stream correctly in terms of the file format. It would seem unnecessary to do this, since, after all, you have just asked to trash this file.

I would also say that, in my humble opinion, finding the correct local directory where the broken file is takes several steps more than just going to and downloading the file from there (unless, of course, it has forgot your password YET AGAIN), unless you are on a dial-up connection or something (plus .fit files aren’t that big anyway).

Well, it’s a relatively recent bug. I have that folder saved as a favorite, so it’s very easy for me to access: It is quite a bit more effort to go log in, find the correct file to download, download it, then go find where it’s downloaded to, just to upload it somewhere else (garmin does not forward third party files even if I do say to save it when quitting).

Maybe it’s my stupid fault for pressing the trash button, but still it bothers me to have the files saved on my computer that are useless. And it bothers me even more that Zwift can make them usable but doesn’t. They were a convenient database of training sessions.

“finding the correct local directory where the broken file is…”? Not if you have a shortcut. One can also use the “Open Logs Folder” menu in ZwiftLauncher app which sits in the notification area (Windows) to get (close) to the desired directory.

Point is, it used to work (admittingly, I’ve never tried uploading a FIT file for trashed session… and able to upload completed session’s FIT file without issue) - and this is they way @Mathew_Bittleston prefers it (and it seems a perfectly valid way…)

Why won’t @Zwift fix the issue rather than us working around it?

To me this sounds like writing a text in a word processor, exiting the application without saving and then complaining that the auto-save file is a mess. If you upload the activity, does that at least also produce a working local file?

Is the easy solution to this to just not click the trash can icon and actually save it via zwift?

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I would guess that Zwift’s file system is predicated on the assumption that if you wanted to keep the .fit file then you would save the ride through their system at the end … probably there is some data added to the file to complete it and save it properly that is not added if you hit the trash can.

The analogy of closing Word without saving your work and then having an incomplete auto-save seems quite appropriate in this case.

If you want to upload a ride to Garmin anyway, why not just complete and save the ride and have it uploaded to GC at the end of the ride … that is way easier than the way you are doing it.

Many reasons one may push that trash button and change mind (accident, not wanting to upload to all the same places, wanting to upload to a different place, wanting to use on a local app, etc). For years, those files (that Zwift generates and leaves on my computer) were reliable. If this is intentional, then the files should not stay and zwift should also also not upload to their site; if it’s just shoddy quality control, then the bug should be fixed.

Fair question. You mentioned something in the first post that caught my eye.

Are you not saving & exiting the game after each session? I’m not clear on why you’re not uploading at the end of a ride.

Just save the ride properly, it asks you to confirm if you don’t save so accidentally doing it would be difficult.

If you connect your garmin account it’ll upload automatically then.

The good news is that the new CE system will use the ride data even if it is not saved, so I don’t think the corrupt file will have an impact on CE.

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Zwift does not have a “file system”. It might have caching in place, but file systems are OS domain.

There are actually only two options wrt trashed session’s FIT file:

  • Delete the file…
  • Flush the cache and leave the file workable.

Anything else is simply a bug… or a poor design/implementation choice, one that can and should be fixed.