645M Freeze after FW 6.20

I have tried everything and the only thing that solves the freezing is to disable the automatic upload via WiFi. I opened a ticket to Italian assistance and they keep telling me that there is no problem for them and to send the watch for assistance. It's a shame 

Garmin UK wanted me to do the same but as I'd already had the watch replaced for sawtooth elevation graphs which made no difference, I didn't bother as it looks like a s/w problem to me. I never used WiFi but the watch still froze maybe 1 in 3 times after saving until I started using the back button to get back to the watch face.

Hopefully Garmin will fix this in the next s/w update (if there is one!).

Yes, that's just incompetent support.  They want you to return the device so that they can claim they've resolved your issue. It won't necessarily fix your problem and definitely means you'll be without your device for a time. I recommend not doing that unless you've tried all the other work-arounds (deleting FIT files, changing language to another and then back, soft reset, using the back option instead of 'done', or just living with it if it's not too bad). 

Actually, I returned the device for the elevation graph problem and it did help (although not entirely).  I suspect this particular problem is at least partly hardware related. I've seen people on the Fenix threads say that problems they had with elevation completely disappeared with the larger device.  That is there's a design fault/cost saving on the 645's barometer, which is too tight to the plastic case.  It is easily obstructed, either fresh from the factory if you're unlucky or with gunk collecting over time, which makes the sensor slow to respond and inaccurate. Sometimes cleaning it helps but it's also really easy to damage the sensor just with a toothbrush.  Garmin recommends just washing with water and a little detergent but that doesn't easily remove scale or hardened scum so your experience may vary (depending on how hard the water is where you live and how salty your sweat is etc). 

Yes and no.  It is nice if we help Garmin out, and I get what you say, but in the end it is up to them to test their product properly and to to have good support.

Support: When you raise a ticket, do you get relevant intelligent questions or do you find that you get a script that ignores all the useful information you put in your ticket and you have to go back and forth about 5 times before you get to where you wanted to be at the start?

R&D: Garmin R&D should have banks of thousands of watch simulators, each of which they should be able to run a battery of sample runs through in faster-than-real-time. They should be able to simulate literally millions of hours of runs overnight. That should help _prevent_ bugs. If a persistent bug is nevertheless found, R&D could be concnetrating efforts on running millions of "virtual hours" centred around ending a run and saving it and what happens then.

If there is a repeatable problem, why can't a watch be put in "debug crashdump" mode where it logs what it's doing and we can send that log to Garmin?

I literally tried all the workarounds suggested in this thread. It still freezes randomly, probably every 5-6 activities. Already contacted support and they told me it's an issue they are aware of.

Agree.

George made a comment (that I now can't find) that the forums are more for end-users not for customer support so providing extra information is really useful to the community. Right, I was not thinking that way but he's totally correct. Very good point.

The only ConnectiQ apps I have are data widgets from RunPower and StrydZones (both deal with getting power info from a  bluetooth/ANT+ footpod).

It has been suggested that this is somehow related to Wifi or Bluetooth. I don't know.

I had only one freeze since i bought the watch (Last year). I use the watch in Portuguese and made a 10km run with music (using a Jaybird X3 and a Spotify playlist). I stopped the activity and turn the Jaybird off... no phone close... When I was at the elevator close to my apartment I saved the activity and the watch frozed.... That was the only time I saved a workout close to my wi-fi but other users reported freezes even far away from their wi-fi... As CIQ I only use Running Power from Garmin... That is all I can report from my single freeze

Garmin prefers to put new products on the market instead of helping us or getting a product out of error.

The bug exists since several versions.