I've got a Garmin 800 which, since it's an 800, is relatively old.
The past few days I've been using it on a commute to and from work.
Before I set off, I give it time to find the satellites and all is good until I've gone 300m-2km and then the speed display drops to zero and it doesn't record distance.
Switching it off/on again starts it normally for another few hundred metres and then it stops displaying speed and distance again.
When I upload to Strava I can see the whole of the route that I've done but the recorded distance is only a few hundred metres.
Any ideas ?