Can the Unity editor break out of an infinite loop in a script?

Short answer - unfortunately, no - if you have already got Unity frozen in an infinite loop, your only option is to force-quit.

However, this question makes me wonder why you're putting an infinite loop in there on purpose in the first place. What are you using it for?

In general, in Unity, you would use the Update() and FixedUpdate() functions for "game loop" type code, because these functions get called every frame, and every physics step respectively, whilst releasing control to Unity's other systems (rendering, physics, etc) between steps so as to not lock up the entire thread. Eg, to some action every frame:

function Update() {
    // increment a variable 'i' by 1 each frame:
    i++;
}

Another method of creating a non-hanging loop is to use a Coroutine, which is a type of function which allows you to explicitly specify certain points where the execution should be paused and control released to other processes until a certain time.

An example of a "non hanging" loop in a coroutine, in Unity's Javascript:

function MyLoop() {
    while (true) {
        print("hello world!);
        yield;
    }
}

And in C#:

IEnumerator MyLoop () {
    while (true) {
        Debug.Log("hello world!);
        yield return null;
    }
}

Hope this is helpful.

Apologies for the slightly off-topic response. However, when people get into an infinite loop and think they've lost their scene and come looking for help on this thread, this will be most useful to them:

without starting unity again. This is important, DO NOT start unity again Go into your game folder (in myDocuments usually I guess) Open the Temp folder in the game folder and look for a file called " __EditModeScene " Rename this file to the name of your scene in unity that was running when it crashed, so myScene.unity or whatever. Take this file and paste it into the Assets folder in your game folder, overwriting(or preferably backing up first) your scene of the same name. Open unity again and your scene will be exactly as it was when you pressed Play and crashed the program.

You're welcome.

Hi @MvD !

Yes, it's possible with a plugin that I created which breaks infinite loops through a single shortcut.

With it, just press Shift+Esc and the editor is responsive again in a flash.

You can watch it in action here: https://youtu.be/USquReimPGE

I'm offering it on the Asset Store, it's called Panic Button :) http://u3d.as/hpe

I think it would be better to avoid an infinite loop as it is likely to make most IDE's hang (at least temporarily).