Factorio Forums

Hosting a local multiplayer ("Host saved/new game") and unticking the save options in the dialog will silently modify global game settings on your local instance of Factorio, in that it will simply turn OFF autosaves globally!
There is no indication that this is what will happen and that it will persist after the multiplayer session.

Seeing how these options are for the multiplayer game only, it should only ever affect said multiplayer hosted games and NOT your local settings.

The game silently turning off autosaves cost me hours on my save game, after suddenly a mod threw an error several hours in and the game had never autosaved simply because a checkbox was unticked in a dialog specifically for hosting a multiplayer game.

I assume you mean the "Autosave interval" checkbox in this dialog: I agree it definitely does NOT seem like changing items in this dialog should change anything else. It would be expected that the next time you return to "Multiplayer server settings" it would remember what you chose there, but there should be a separate copy of those settings for single player.

It has worked this way since 0.15.0 and I don't see anyone looking to change it any time soon.