How can I interrupt auto-end-turn?

I don't believe a hotkey for that is implemented. You could hit Control+O to get into the Options, and change it there. I think that's pretty much the fastest option in Civilization...

ESC...

It ends the turn, bringing up a menu, effectively a "pause". Unfortunately, at that point, you have to dig through the menu, to unselect the option to disable the auto-turn-end.

No other menu will interrupt the process. The game will continue to run, behind the screens, including the in-game selection menus, where it honestly should be pausing the game.

I agree, this needs a readily available, simple, toggle on the UI screen. A simple three-stage RED/YELLOW/GREEN cycle, unless you only want RED/GREEN for on and off. Yellow being some custom tween phase, with a nice little delayed time-pause, at the end, where you can jump right to STOP, next. (Yes, on a fast computer, and in some actions, things fly by too fast to even figure-out what is happening at all.)

Honestly, having the option, with a little pop-up screen, would be nice. Let you pick the things you want to "skip", or things you want a "full-stop" on, for automation. (Having smart AI auto-explore would be nice. As opposed to having it be a full-stop, every time. Duh... Get the huts and avoid bandits and enemies!)

The one feature, which still has higher demand than any of the crap they added in every version, yet, they still have not added this simple feature. (This is one of those "play it my way", games. "They", being the developers, who rarely actually play the game, beyond testing. Or, they only care about how they want to play it. It's a total hacked oversight. Which is why they still don't have it working right, when it is on. Thus, everyone just surrenders and turns it off, eventually, forever.)

Actually, what we need is an "Auto-play, while key is pressed". Something like the "Space-bar", so we can just hold it, or rest something heavy on it. While it is being held down, it runs blind, in auto-end-turn. Let go, and it stops on the next possible turn, which is yours. Pure, "Keep it simple stupid", solution, by "Keeping it stupid simple".

Maybe on Civ MCXVII, we will get this feature.

I FOUND THE PAUSE BUTTON FOR AUTO END TURN. Left-click a unit, right-click the unit. Game pauses.

This reply is years late but valuable enough for anyone who is still playing the game (like me!). The pause button is 100% reliable, instant, dead easy to use and gives you a very generous usage window. (It does require having at least one (non-caravan) unit.)

First order a unit to do something (improve a tile, fortify, etc) then, when you want Auto End Turn to pause you simply left-click the unit, right-click the unit. Done. (both clicks within the hex, not somewhere else) Left-click selects the unit, right-click cancels it’s orders, Auto End Turn pauses until the unit is given new orders. No hotkey required, just a double-click.

You can do this at any point up until the start of your next turn (if the Next Turn button appears then it’s too late), plenty of time to notice something like a new Religion being founded and what not, especially since you still have the City-State’s and Barbarian’s turns to go through.

That’s it. Double-click: Instant pause.