Solution: you need to delete .meta file,which is usually stored in a folder where your project files get saved by default.
In my case .meta files was at this path: /Users/amitb/Documents/Adobe Flash Builder 4.
How:1. Go to : /Users/amitb/Documents/Adobe Flash Builder 4 (please specify according to your system, where your flash builder project is saved)
2 .what???…you are not able to see .meta…..oh yeah its because its a hidden file.
3. So here its a nested TIP you can say(How to Enabling hidden files in MAC finder)
3.1 Open the terminal (found in /Applications/Utilities/)
3.2 Type the following (without quotation marks) to show hidden files: “defaults write com.apple.finder AppleShowAllFiles -bool true”
3.3 Hit enter
3.4 Type the following (without quotation marks) to restart the Finder: “killall Finder”
3.5 Hit enter(this will re-open the finder with all the hidden file also visible now)
4. Now you can see .meta file
5. Just delete it…Problem solved..Hurray!!!
My system specification: > MAC OS X version 10.6.8
> Adobe¨ Flash¨ Builder™ 4
One more thing, if you want to revert back your default view(do not want to show hidden files in finder) just do step 3.2 with false option.