I am having this issue, too. I was about to start a new thread, when I saw the forum suggest this one.
I can have 10 tabs open with changes, close Atom, and there is no prompt to save anything. There doesn’t seem to be anywhere that I can find to specify an option to prompt to save changes, either.
Are changes saved to a buffer somewhere like what is mentioned here? Maybe. I don’t know, because the next time I open Atom it only shows me the page I just opened. I never get any indication that there are unsaved files floating around on my Windows 10 PC somewhere.
What am I missing?