To enable or disable the preservation of open files between launches, there's a global Preference/Setting.
up to Monterey
System Preferences > General > Close windows when quitting an app
System Settings > Desktop & Dock > Close windows when quitting an app
On Mac, this is known as a savedState. I can as a one-time option prevent any app from using its last savedState by holding Shift ⇧ as I launch it. I could discard the SavedState itself from
~/Library/Saved Application State/ …
But what if I just want one app, say Preview, to never save state, without having to disable this globally.
I'm writing this to be a googleable resource to an issue I once found the answer to, then completely forgot; which made it really hard to find again. Having re-discovered it, I wanted to nail it here, hopefully in searchable form.