How to delete all history on FR970?

Probably can do it from Garmin express. 

Ah, got it; that was going to be my next guess (it's the one place I didn't check); I GUESS I can understand the logic in that (put all resets/deletes in one place), but it seemed to make more sense to me to keep it with History like it had been.

- Tim

Yes, the 965 has this ‘erase all activies under’ in both system settings and history.

I believe I have never used the function. Except for resetting (total) the watch when selling. Just curious, why erase? 

To make more room for more activities? Why would I want to keep activities I've already sync'd with Garmin's servers on the watch, taking up space?

I'm not aware of any process these watches have for automatically cleaning off older files to make way for new ones, are you?  If so, that would be news to me.  I'd still want to remove old activities files after they've been sync'd, anyway.

- Tim