As per title, but how the hell do I get back to normal screens. Even rebooting makes no difference. Many thanks if anyone knows

Check that a button isn’t jammed in.

Mine did that, you have to do a full factory reset to get it out of the loop. Can’t remember the buttons you hold down and in which order but it took 2-3 attempts for it to work.

Had similar a couple of times a few years back. I vaguely remember simultaneously holding the power & right key (I think) for like 1 minute (longer than you think you should).

You’ve not got many options really. Hold some key combinations for a while and see if it restarts.

Oh, and make sure the memory card is taken out. I had this cause a hang once so its worth getting it out of the way!

The Garmin online chat support is pretty good, especially if you are in the UK.

My watch did that, then it heated up and died 🙁

wasn’t an 810 on a positive note.