29 Mar 2011

VerifyError: Error #1024: Stack underflow occurred

AIR AS3, FlashDevelop 3 Comments

Wow – I’d never seen this one before. So I’m putting up here to remind me what to look for if I ever see it again!

Basically I had a SWF that ran fine in debug build mode in FlashDevelop but if I set it to compile as a release version this error soon appeared.
On closer inspection it turns out that in the line that was crashing (which was hard to find in itself) I was using a variable named “h” in a loop. The clue was that this var h:DisplayObject was coloured green by the compiler and therfore most likely an internal variable in a parent class. All I did was change it for something a bit more descriptive and unique and it all compiled. So lessons learnt – listen to the code highlighting hints and don’t be lazy and use short variable names!


A bit of searching also suggested that it may be a Flex 4.1 SDK related bug as I would have assumed that the compiler would give you a warning even when compiling a debug version. If anyone can shine any more light on this one please post.

3 Responses to “VerifyError: Error #1024: Stack underflow occurred”

  1. steve says:

    I’m having similar problems, I’m getting stack overflow error when doing a release build, but it works fine with a debug build.

  2. Paul says:

    I have also come across this exact issue (works in debug, stack underflow in release). In my case, it was fixed by remove a trace from a function called by the faction the stacktrace claimed the error was in.

  3. Conom says:

    Hi, I have this problem too. My code is:
    _streamClient.onPlayStatus = function(o):void
    for (var s:String in o)
    //trace(s + ‘=>’ + o[s]);

    when I remove coments before trace everything is OK. Epic

    Sory from my english 🙂

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