This is a pretty old issue that should have been fixed in version 6.75 but still seems to be an issue.
Using the Swimrun activity always (at least for activities longer than say 20mins) creates a corrupt .fit file that is impossible to fix using the normal tools or to sync to Garmin Connect. I have been in touch with Garmin Support last year (mid 2017) and they said it was going to be fixed in a future release, and once ver 6.75 was released the release notes pointed into that direction. However, now running on version 8.00 the issue is still there. I have talked to a number of friends using Fenix 5 that are also experiencing the same issue.
However, searching in this forum gives not much of input, either there are no fellow swim runners posting here or I'm the only one experiencing this. I have tried multiple times to factory reset the watch, beta versions of the SW, all with the same result: Only corrupt .fit files are generated by the Swimrun activity.
So, do the community have any advise to me? Garmin Support seems to be a dead end. I would only guess the amount of tantrum by the users if e.g. the Triathlon app behaved in the same way...
