Garmin Died Mid-Ride? Recover and Merge It

Does Garmin save an activity if it dies?

Yes. Your Garmin saves everything it recorded up to the moment the battery died. Edge bike computers and Forerunner, Fenix, Venu and Instinct watches all write the activity to a .FIT file on the device as they go, not when you press Save. A dead battery mid-ride, or mid-run, costs you the last few seconds at most.

What is not saved is everything after the screen went dark. If you kept going on your phone, a second watch or a friend's unit, that part lives in a second file. Neither Garmin Connect nor Strava will join the two for you, which is why so many people upload one half and lose the other.

The fix takes three steps: find the partial file, get it off the device, and merge it with the second recording. Each step is covered below.

What Garmin writes to the .FIT file before it shuts down

A Garmin records in the background the whole time the timer runs. Every second (or every few seconds in Smart Recording) it appends a record with your position, speed, heart rate, power and cadence to an open .FIT file. When the battery gets low, the device shows a warning and, on most current firmware, closes the file cleanly before it powers off.

If it powers off before it can do that, the file is truncated, not corrupted. The ride data is intact. What is missing is the summary block at the end: lap totals and session totals. Garmin Connect may refuse a file like that with a "corrupt" or "unable to process" message, but the data is still there and a repair tool can rebuild the summary.

Where to find it once the device is charged and connected by USB:

• Edge bike computers — Garmin/Activities/. The unit mounts as a USB drive on macOS and Windows.
• Forerunner, Fenix, Venu, Instinct and Enduro watches — GARMIN/Activity/ (older models: GARMIN/ACTIVITY/). Recent watches use MTP instead of a plain drive: they show up in File Explorer on Windows, and on macOS you need an MTP client such as OpenMTP.

Files are named by start time (2026-09-20-08-15-32.fit) or by a short hex code on newer devices. Sort by date and pick the one from the ride that died.

Why did my Garmin die mid-ride?

Almost always the battery, and usually for one of these reasons:

• Cold — Lithium batteries lose capacity fast below freezing. A unit that reads 40% at the top of a winter climb can shut down on the descent.
• Battery age — After two or three years, a Garmin that once lasted 20 hours can be down to 8. The percentage shown gets less reliable too, so it jumps from 30% to off.
• Power-hungry settings — Multi-band GNSS, an always-on backlight, map navigation, music, and a constant Bluetooth link with notifications each shave hours off the runtime.
• It was never full — Dirty charging contacts, a loose cradle or a cable that only powered the screen. The device said 100% at 11 pm and had 60% at 6 am.
• A crash, not the battery — If the device rebooted and came back with plenty of charge, that was a firmware crash. The activity is usually saved and offered for recovery on the next boot.

Whatever the cause, the partial file is on the device. Prevention comes next; recovery is one section further down.

How to stop it happening again

• Check the real charge before you roll — Plug in, wait for the charging icon, unplug at 100%. Clean the contacts if the charge seems to stall.
• Switch to a battery-saver power mode — On Edge units, Battery Saver lowers the screen and GPS rate and roughly doubles runtime. On watches, pick a power mode with single-band GPS (UltraTrac or Max Battery) for anything over four hours.
• Turn off what you're not using — Maps you're not navigating with, backlight on gesture, music, phone notifications, and paired sensors that aren't on the bike today.
• Carry a small power bank on long days — An Edge charges while it records. A 5,000 mAh pack weighs about 100 g and refills an Edge twice. Some watches also charge mid-activity with the cable attached; check your model.
• Know your number — If the unit lasts 12 hours in the mode you ride in, plan around 8. Battery estimates are optimistic and the last 10% goes fast.
• Start a backup early — On epic days, run Strava or a second device from the start. Overlapping recordings merge just as cleanly as back-to-back ones.

Recover the partial activity: Garmin Connect or USB

Charge the device before you do anything else. Most Garmins that shut down mid-activity offer to save or resume it on the next boot; pick Save, not Discard. Then try the routes below in order.

1. Let it sync — Open Garmin Connect on your phone with Bluetooth on. If the file closed cleanly, the activity appears within a minute and you can skip to the export step.
2. Export from Garmin Connect — Open the activity on the Garmin Connect website, click the gear icon and choose Export Original. That gives you the .FIT file with every sensor channel intact.
3. Copy it over USB — If Connect never shows the activity, or shows "file is corrupt", plug the device in and copy the .FIT from the folder listed above to your computer. USB always works, even when sync doesn't.
4. Repair it if Connect rejected it — Open the copied file in TrailBlender. It rebuilds the missing summary block, and the repaired file uploads to Garmin Connect and Strava normally. The corrupted Garmin file guide covers what to do if that isn't enough.

Then export the second half. From Strava: activity page, three-dot menu, Export GPX. From a second Garmin: the same Export Original. From Wahoo, Coros or Apple Watch: export .FIT or .GPX from their app.

Merge the recovered file with your second recording

You could splice the two by hand: convert both to GPX, find the timestamp where the Garmin stopped, paste the second track after it, fix the XML. That takes 30 to 60 minutes and one wrong character breaks the file. TrailBlender does it in under a minute and keeps power, heart rate and cadence from both files.

1. Download TrailBlender — Get it for macOS, Windows or Linux. A two-file merge is free, and it runs offline, so your files never leave your computer.
2. Drop both files in — The recovered Garmin .FIT and the second recording, in .FIT or .GPX. No conversion needed.
3. Check the timeline — TrailBlender lines the files up by timestamp. A back-to-back pair is sequenced; an overlapping pair (backup started before the Garmin died) is aligned and de-duplicated.
4. Pick a source per channel — Keep the Garmin's GPS and power for the first part, the phone's GPS for the second, and heart rate from whichever device wore the strap. The power and heart-rate guide shows how to do this channel by channel.
5. Export and upload — One .FIT or .GPX with the complete ride. Upload it to Strava, Garmin Connect or intervals.icu as a single activity, then delete the two halves.

Two Garmin files from the same ride, say an Edge that died and a Forerunner that kept going, merge the same way. See merging FIT files for the FIT-specific details.

Checked 19 October 2026: Strava’s manual upload limit is 25 MB per GPX, TCX or FIT file. Check the exported file size before uploading.