Garmin Connect 4.12 keeps crashing - UPDATE

Did this as well, although I'm in Amsterdam.....

Go to Apple Health Connections and put off all categories (all data will be gone)
Go to IOS Settings and put your time zone on Algiers (Is also GMT +1 as Amsterdam, but no Daylight Savings) apparently Reykjavic works for UK.
Sync your connect data
Go to Apple Health and set all connections on again.
Sync your connect data (I did it a few times)
Go to IOS and put your time zone back on your original.

Seems solved for me now. (fingers crossed)

To be honest, Issue seems to be with Apple Health rather than Connect. As I individually connected only weight (1 data point per day) it already worked. The syncing seems to crash because Apple Health can't cope with the overlapping data (as the Apple Watch 4 issue)
Do hope this works for you as well,

Let's get rid of DST!

Thanks ! This solution solve the problem !

setting timezone from auto / Berlin to Island, one sync with mobile connect and then back to Berlin... now everything is fine for 1 year. switching forward to DST in spring (23hour day) will most probably work ;-)

Thanks for all the help, I had tried everything except changing timezone out of DST. Set to Iceland, connected the watch again, all fine now. By the way, same problem with another app, but there the change of timezone didn't work.

Connect Mobile 4.12, iOS 12.0.1, iPhone X, keeps crashing on virtually any activity in the More menu.
I was trying to add a new Index Smart Scale, but whenever I go to the Add Device, the app crashes.
and if I cannot add the scale, it cannot be used. Maybe I’ll have to return the scale...

I have the same issue since the DST kicked in. Maybe Garmin have an update??

This issue has been escalated internally and has been given the highest priority available. We will be closing this thread and then opening it again to post when a resolution has been found.

Our current work around that we have found to work for many customers is: Open Health app -> Go to sources tab -> Hit "Connect" -> Hit "Turn All Categories Off"

A fix for the issue has been determined and we expect the fixed to be released in the very near future.