Garmin watches should nail one basic thing, track your run and send it to Garmin Connect without any fuss. Lately a lot of people say that handoff breaks, because the watch saves a dodgy FIT file that will not sync to Garmin Connect or Strava.
What makes it hard to ignore is how consistent it looks. This is not a one-off after a dead battery or a sketchy cable. The same symptoms keep popping up on Forerunner models like the 255, 955, 965 and 970, plus higher end watches like fēnix and Enduro. Some people see it on runs, others on walks, rides and even multisport sessions. The giveaway is always similar, an unusually tiny file for a long activity, then missing GPS and the usual second by second data when you try to upload.
What the corruption looks like in the real world
The clearest technical explanation comes from an unexpected place, a third party FIT repair site that suddenly started seeing lots of the same broken files. Once you line them up, the pattern is pretty clear.
The file technically exists and includes a file_id message, but the values inside it are wrong. Large parts of the data stream are missing, especially the record messages that normally capture second by second data. Event and device info entries can vanish too. What sticks around are the summaries, things like activity, session and lap.
It gets weirder from there. Some files show duplicates, two identical activity entries, with laps and sessions repeated. That points to a save process that kicks off, trips over itself, then retries and only half succeeds.
The repair tools can sometimes patch things up enough to let the file upload again, but they cannot recreate data that was never saved. That is why the fixed activities often have no map or charts. You end up with the outline of a workout, not the run you actually did.
Why runners care more than Garmin seems to
If you run now and then, losing a map is annoying. If you follow a plan, it can mess up your whole week. Some people link it to PacePro, courses, stopping navigation mid run or using resume later. Others hit the same problem without doing any of that. The trigger seems fuzzy, but the frustration is the same.
You finish a long run, glance at the watch and everything looks normal. Distance checks out. Effort looks right. Sometimes the watch even flashes a personal best. Then the sync fails, the file turns out to be just a few kilobytes and the activity either never shows up in Garmin Connect or arrives stripped of the data.
It gets worse once you try to work around it. When you fix the file and upload it by hand, Garmin’s own system often treats it like it never really happened.
Bugs are part of software. What really winds people up here is the lack of resolution. There are forum threads that have been running for months, with plenty of replies, but no fix incoming. Some support responses lean toward hardware replacements or vague talk about random corruption, without ever clearly saying yes, this is a real issue and we are fixing it.
What you can do right now if you get hit
There are a few things you can do if you come across the issue. Start off with some damage control.
Before you poke at anything, copy the original FIT file off the watch and stash it somewhere safe. If the activity is sitting in a pending folder on the device, grab that as well. After that, try syncing again anyway. A few people say it randomly works on a second or third attempt.
If it still refuses to upload, a repair tool can at least get the file into Garmin Connect. Just keep your expectations low. You might save enough to keep your weekly mileage and training log intact. The map and graphs might still be gone for good.
After that, contact Garmin support and be very clear about what is going on. Mention the tiny file size, the missing data and the duplicated sessions. Send them the original corrupted file and the device logs if they ask. Push for an internal engineering ticket and get a case number so it does not vanish into thin air. At this point, runners deserve more than a vague apology and a suggestion to use a third party website.
Sources: Garmin Forums, Garmin Support, Fitfileviewer
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