Fenix 6 pro stops tracking mid-run

Ysterday with a 6 Pro on 25.10: after 1 km saw that the 6 Pro had spontaneously returned to the watchface, after pressing Start the timer was still running but the recorded distance was 600 meters. Livetrack had stopped tracking at 600 meters. It took a minute or so before the 6 Pro had regained its bearings. My 6X on 26.00 on the other hand was doing just fine. I updated the 6 Pro to 26.00 now. 

I have seen this behavior before with a Fenix 5 Plus, but not often. 50% of all runs seems a bad problem.

I should qualify that 50% of the time comment as it's not entirely accurate. It can happen a few consecutive runs and then not for weeks. It's truly odd and unpredictable.

I'm always using the latest GA firmware. So last run yesterday was on 26.00 which is happened. It's happened on all prior firmware over the last 12 months or so on my Fenix 6. As mentioned, also happened previously on the 945.

I feel somewhat relieved to hear that I'm not the only one who has experienced this issue. It seems there must be a fundamental problem that his happens on different models and different firmware. Garmin support were unable to find a root cause on my 945 despite providing logs etc. They tried claiming it was somehow related to either a watch face or data field. Sounded like BS and clutching at straws to me.

It's super frustrating as it totally throws out metrics for the entire run.

I am almost certain it is not watchface or data field or even software version related, my 6 Pro is completely as-delivered with only user settings and some sensors configured. I'll have a look at the 6 Pro's eventlogs later tonight. 

The couple of times this happened to my devices was in roughly the same location, shortly after entering a park with dense tree cover, where all of my GPS devices over the years have struggled to get signal. Recorded tracks are mostly squiggly in that park, with any Garmin, or Suunto, I only run there when it is very sunny and I need the shade. Which may explain why I encounter this issue rarely. 

Obviously something is not right with handling unexpected or invalid or no GPS data under certain circumstances.

I don't know if it is worth the trouble for you, but I always run with two devices, being a bit of a collector I have a couple of old devices I take out regularly anyway.

I think you could certainly be on to something that it relates to a weak GPS signal. I have two main circuits that I run and it is happening in a shaded section. The second one though really doesn't have dense tree coverage though.

What's perhaps odd though is I can pass that same section twice on a single run (doing loops). The problem has never occurred in t he second loop. It's only ever in the first km (ie first 5 minutes or so). On times when the watch doesn't play up, the track in that area appears pretty good. So perhaps it's a combination of tree coverage and satellite position.

What's most disappointing is Garmin support engineers couldn't see any issues despite providing them with logs from numerous occurrences of this happening.

I hear your point about running with multiple devices. However, I expect an expensive Garmin device  to work or for them to be able to resolve this problem.

If you're able to pinpoint any more specifics I might go through the hassle of opening a new support case with Garmin and point them to this thread.

I had a look at the debug folder and eventlog file but it had nothing logged of interest at the time of the problem.

It is indeed _always_ only in the first 1 km. My "problem park" is only a problem at the start of run, never at the end. It has happened during walks and runs.

I have not looked at the FIT file of the run yet. I am going to send it to Garmin Support anyway, you never know, maybe it ends up with someone who is interested to learn from it and create improvements.

If you have an open support ticket with Garmin, can you share the ticket number either publicly or privately so I can reference it too please?

Can you send me a PM? I'll reply when I get the case number.

PM sent. Thank you! :)