Do you have an OS X application which is just bouncing in your Dock when you're trying to launch it?

Then this might help:

The problem

For some reason the executable file inside your .app file doesn't have the proper permissions to get executed. The Unarchiver was known to set the quarantine flag incorrectly or the app is just defect. Whatsoever, you'll need to utilize your Terminal if you want to fix it manually or the droplet for an automatic repair attempt:

Manual fix

1. start your Terminal (if you don't now how to do so you should take a look at the automated version below)
2. type in chmod +x (with a trailing space!)
3. rightclick your application and select show package contents
4. navigate to Contents » MacOS
5. drag the file in the opened folder onto the Terminal window (this will insert the filepath there). If you have more than one file in the MacOS folder you have to decide which might be the right one and if you weren't lucky you'll have to try them one by one, sorry!
6. Press enter, you should be fine now. Have fun with your app ;-)

Automatic fix

I've build a little droplet which probably can solve your problem by just dropping the defect application onto it. If it does not work it's probably something different or there were too many files (see manual fix #5)

Thanks to the test bunny ;-)