Caltopo appears to work fine when no map is specified. Just opening Caltopo displays a map of wherever I last left off.
However, if I try to open a map I have previously created, Caltopo basically goes nuts on my Win 10 laptop. The CPU percent on my Chrome task manager shows up to 120%, indicating that multiple cores are being used, and the memory allocation exceeds 1 Gb. Despite using that much CPU and memory, the map never is displayed, and I have to kill the window.