F5 reboot under outdoor cycling activity.

Same here. I believe it has something to do with the phone syncing; it doesn’t happen when I leave the phone home. Been happening sinc is 8. A real pain in the....

I was thinking about the same so i turned off my phone after first reboot, but i happened again later with phone off... :(

Same Problem! I use the Beta Firmware 8.54. I use HRM Tri, Di2, Garmin Speedsensor, Power2max neco. Only if I turn off the bluetooth connect to the phone it will be works....:(

Thank you all for the information but we are not able to reproduce this issue in-house so could you provide us with more information.

Does resetting defaults on the fenix 5 resolve the issue? (Settings -> System -> Restore Defaults)
What software version where you running? (Settings -> About)
What sensors were you running?
Has this happened on any other activity type?
Did you have the fenix paired to a phone?
If so, what type of phone and was the screen ON or OFF when the issue occurred?
Was the Connect Mobile app running when the issue occurred?
If Connect Mobile was running, was it in the foreground or the background?
Was LiveTrack running when the issue occurred?
Did any out of the ordinary events occur on the phone when the issue occurred?
List of Connect IQ Apps, Widgets, Data Fields or Watchfaces installed on the device?
If Connect IQ apps are installed, does uninstalling them resolve the issue?
Was there anything different about the activity when it happened? (Different bike, new handlebars, sensor, …)

Same here with my F5X under 8.54beta : 7 reboot during a hours run (trail activity) :mad:
Strange because I have installed 8.54 for 1 month and it's a new issue. I had also my iPhone with me connected to the F5x (iPhone in my pocket, screen off, GCM running with a live track activated, actually a Strava beacon), ... and a HRM-Run + Stryd sensor

Garmin-Heath : I understand your request, but to many question !! Is there a way to send you a condign file to obtain those data ? I have an error log file available if you want !

Thank you all for the information but we are not able to reproduce this issue in-house so could you provide us with more information.

Does resetting defaults on the fenix 5 resolve the issue? (Settings -> System -> Restore Defaults)
What software version where you running? (Settings -> About)
What sensors were you running?
Has this happened on any other activity type?
Did you have the fenix paired to a phone?
If so, what type of phone and was the screen ON or OFF when the issue occurred?
Was the Connect Mobile app running when the issue occurred?
If Connect Mobile was running, was it in the foreground or the background?
Was LiveTrack running when the issue occurred?
Did any out of the ordinary events occur on the phone when the issue occurred?
List of Connect IQ Apps, Widgets, Data Fields or Watchfaces installed on the device?
If Connect IQ apps are installed, does uninstalling them resolve the issue?
Was there anything different about the activity when it happened? (Different bike, new handlebars, sensor, …)

- Have not tried resetting defaults on fenix 5. Will NOT erase all recorded data unless I really have to. Recording training data is the reason I bought this watch....
- SW 8.54 public beta.
- Garmin HRM-Tri and Garmin speed and candence sensors. (speed/cadence 010-12104-00)
- Paired to iphone 6 ios11.3 at first, later turned off phone. Same issue.
- No live track running.
- Nothing different about activity, have been running 8.54 without no issues earlier.

Today I went for a 48km long bike trip. Removed speed sensor, only HRM and cadence sensor connected. And no phone. NO ISSUES.
Was it the speed sensor? Was it the phone? I dont know. But as said earlier, I had my phone on and reboot happened, I turned phone complete off, happened again.
This time no speed sensor, no reboot. Coincidence?

Had some reboots during cycling activity, too. Running on FW 8.54 with cadence, speed sensor and HRM Running. During one hour of activity two reboots. After the reboot it was possible two resume the acitivity. After reset (holding the upper left button for 20 seconds) of the F5 the problem is fixed so far.

Does resetting defaults on the fenix 5 resolve the issue? (Settings -> System -> Restore Defaults) No
What software version where you running? (Settings -> About) 8.54 beta
What sensors were you running? HRM-Tri, Speedsensor, Powermeter (p2m neco & p2m classic), Di2, Somtimes Garmin Tempe,
Has this happened on any other activity type? No
Did you have the fenix paired to a phone? Yes
If so, what type of phone and was the screen ON or OFF when the issue occurred? Android 8.0 & 8.1 both
Was the Connect Mobile app running when the issue occurred? Yes/no
If Connect Mobile was running, was it in the foreground or the background? Both
Was LiveTrack running when the issue occurred? Yes/no
Did any out of the ordinary events occur on the phone when the issue occurred? No
List of Connect IQ Apps, Widgets, Data Fields or Watchfaces installed on the device? Watchface (line), Battery Analyzer, Weekly Step Traget, Sun an Moon
If Connect IQ apps are installed, does uninstalling them resolve the issue? No
Was there anything different about the activity when it happened? (Different bike, new handlebars, sensor, …) No

Thank you all for the detailed information. We are looking into this issue and we will post any updates in this thread in the future.

I experienced the very same issue while I was using running app.

https://forums.garmin.com/forum/on-the-trail/wrist-worn/fenix-5-5s/1322037-fenix-5-5s-reboots-itself