GPS PROBLEMS

Go to settings> > system> about and press 'down' until you reach the CPE info page. Does it say "CPE Current"? 

When you are there, also check what your GPS software version is

Hi, thanks yes it does say current 

26.00 (c7a16d5) software version 

Okay, that is your main software version. What I meant was that GPS software version. Somewhere on these pages it should say "GPS 6.60” (among other text)

GPS 6.60

Okay. That's what it should say. 

So how is the behaviour exactly? When you start a run, it is searching for GPS but doesn't find it, so the GPS "arch" stays red?

Yes, that's correct, I make sure I'm outside but the arch stays red, it started doing this earlier last month, but I also noticed in December it would map part of the run, then stopped altogether

Unfortunately I don't have another proposal as to do a full reset of the watch. 

Your CPE file may be corrupted. I'd delete all files inside the  RemoteSW folder of the watch and then sync with Garmin Express. Try this before attempting a full reset.