juno run file stopped working

I am a Julia beginner but very experienced in many other langs/ecosystems/ides etc
I was using Atom/Juno no problems for about a day and run file worked fine. Now it has stopped but I did not do anything different… I restart Atom, create a new jl file, but cannot get it to compile. ie shift cntl enter
Scary. Any ideas cause I am totally stuck.
Thanks