It happens many a time ...but you can solve it in 3 ways

1) Clean the project and try.

2) Close flex builder and reopen it. try it...If that doesn't work than go for 3 option

2) Change your workspace and import that project in it or best is create new one and make the changes in it...

Sometimes the workspace get corrupted and so it happens...

If this post answers your question or helps, please kindly mark it as such.

I had the exact same issue. It appears the problem is an auto updater in Chrome that installs a non-debug version that trumps the debugger.

Found the solution here:

http://www.timo-ernst.net/2010/04/chrome-flash-debugger-not-connecting -to-flexflash-builder/

Cheers!

I get this issue ~ 40 times a day and it is extremely frustrating.   I have tried reinstalling flash builder, uninstalling anything that I think might affect it (fiddler & servicecapture), and have tried chrome, firefox, and internet explorer as my default browser for flex to no percievable difference.  The only recourse is to force a project clean and rebuild - which is absolutely horrible as the app I work on is ******* huge and basically adds about 2 minutes everytime i want to do a build.  Soooo frustrating....     

Hi,

I have a problem when running debug in my Flash Builder 4. When i click on the debug button, when it launch i have ERROR 404 showing up in my browser.

I have check the debug folder path and compare it with the browser they are the same. I noticed that the index.html is missing. Then i tried to copy the index.html from my release folder and somehow it run. But the when i run the debug again, it shows the ERROR 404 in my browser. Somehow it deleted the index.html that i copied from the release folder. 

Anyone experiencing it?

Regards.

Cris

What's in your html-template folder?

Well that's your problem. You should have a index.template.html file in there. I'm not sure how you would regenerate this, but try going to Project -> Properties -> Flex Compiler and then try changing around some of the settings for HTML Wrapper. This should trigger a regeneration of that file.

Nah, stuff happens. It probably got deleted on accident. I personally wouldn't bother with a bug report.

Glad you got it worked out.

Just an FYI, for anyone encountering the issue where the debugged sporadically connects to the browser debugger... Download the flash projector (stand alone) debugger.  Edit the projects debug settings and in the url to debug change the .html to .swf.  Instead of luanching in a browser it will launch in the stand alone flash projected application and connect every time.   Happy Coding.   For even more awesomeness use HellFire Daemon Compiler... its freaking insane!

I am having the same issue however it's an AIR app so it is already a stand alone. Any ideas on this?

Hi all,

I ran into the same issue today and found this page while searching for help.

None of the suggestions helped. But there was a suggestion to debug in flash itself. So I opened the .html file from bin-debug in the flash builder itself - basically double click, and it worked in the builder. Now the surprising part is I had not closed the applications I'd started for debug, these  were still stuck at 57%. These started opening in my browser with debugger version of flash player!! And it was debugging fine!

Guess the trick is to click on the .html file while the progress bar is stuck at 57% for debugging the application. No clue why this works.. I have tried this 2-3 times and it worked always.

hope this helps someone.

I'm having this exact issue with Flash Builder 4.5.1, flex sdk 4.5.1 and air 2.7

My apps are air apps, they run fine, but can't debug. For a mobile application, i can debug on the mobile device, but not on desktop (emulator).

The error is always debugger can't connect to the application.

This is the error when i kill the app before Flash Builder times out trying to connect, it halts at 57%:

Process terminated without establishing connection to debugger.

Launch command details:  "I:\Adobe\Adobe Flash Builder 4.5\sdks\4.5.1\bin\adl.exe" -runtime "I:\Adobe\Adobe Flash Builder 4.5\sdks\4.5.1\runtimes\air\win" -profile mobileDevice -screensize 480x762:480x800 -XscreenDPI 252 -XversionPlatform AND "C:\Users\mia\Adobe Flash Builder 4.5.1\test\bin-debug\test-app.xml" "C:\Users\mia\Adobe Flash Builder 4.5.1\test\bin-debug"

This is the error if i let the process to time out:

The Flash Builder debugger failed to connect to the running application.
Ensure that:
    1. For in-browser applications, you are running the debugger version of Flash Player.
    2. For network debugging on a mobile device, you have a reliable network connection to the device, and port 7935 is open on your machine's firewall.
        Device connection help

Flash Player is really got nothing to do here since i'm trying to debug Air apps.

Debugging worked fine with Flex sdk 4.5 and air sdk 2.6.

After updating to air 2.7 and sdk 4.5.1 i couldn't debug any Air app, mobile or not (although i can debug on the mobile device, however it's a pain to always debug on the device, it's just a waste of time)

I'm using windows 7 64b btw

Is there any solution for this?

Thanks

I don't have wampserver installed nor am I using phpmyadmin on this computer.

I'm having the exact same problem that pin05h is having - debugging in AIR, Flash Builder hangs at 57%, get the same error message every time, not running phpadmin or wampserver. However, when I debug the application, not only do I have nowhere to right click and say Connect (the window does not appear until the error does), but the error only lasts 3 or 4 seconds.

How do I specify that I want the app to run in the browser? And, if we are using AIR-only features (which I'm not sure I am), how do we fix the debugging issue there? Thanks for working to fix this issue.

hi i have the same problem, adobe flash builder keep proceeding on 57%, i tried the solution of disabling chrome plug in but nothing happens, please help

Steps to resolve this issue, on window machine

• Go to control panel -> add and remove programs
• Uninstall Flash player 64 Bit and Flash Player 64 Bit Active X Player
• Re-install Flash Player 32-Bit version Debugger player.
• Exit your browers if required and Restart you IDE.

This solved my problem, i hope it solves your problem with the warning message on debug click in the IDE.

Hi,

I'm facing same issue, "Failed to connect;session time out". For the background, I'm using FB 3 and IE . A strange thing is happening in my Flex Builder though, for one application the debugger is working successfully but for the other its giving this error at 91% launch.

Please suggest.