I was doing speed work interval sessions on my run and the watch crashed in the middle of one of the recoveries. At least it wasn't during the interval itself.
However, it hard reset the watch. I had to go through the watch introduction, set my language, re-enter my age, weight, and sex, etc.
I no longer had the workout programmed, so had to press the lap button manually, keeping an eye on the time. Then stitch the activities together post run.