Running in world age ... while current world is

Where do I find the file startup.jl? Also, I am not sure how I am using eval the way you suggest. Just to be clear, once I re-run the code the second time, I have no issue.

What I do: I create a mutable struct and then a function y that takes it as argument and runs a function x inside. Then I use pmap on the function y. Please let me know if I should provide any more detailed information. Thank you!