Closed Starbound not opening - Mac

Hello everyone!
Today I downloaded Starbound unstable branch on my Macbook Pro. I tried opening it but Starbound won't open. I checked in Activity Monitor to see if it was opened but no trace of starbound. I tried launching starbound again but its says "Failed to launch (App already running)".
I can't close Steam because it says that I have to close starbound before closing steam. What do I do?
Everything worked fine before when I had the stable version.

Thank you

EDIT

#1.I force quit steam and now that I try to open starbound it says "The applucation "Starbound.app" can't be opened -10810"
#2.Changed back to the stable version and it could open, changed again to the unstable and couldn't open anymore

 

Start here: http://community.playstarbound.com/...d-support-thread-guidelines-read-first.83266/

If you're still having trouble after following those steps, post your OS version (10.10.1 has some trouble with Starbound I believe) and the other info outlined in that thread here.

 

Thanks for answering in my thread, I have tried the first steps of deleting some folders, that didn't fix the problem, I deleted the whole folder of starboud at "~/library/application support/steam/steamapps/common/starbound", I then reinstalled it, selected the unstable version and it still won't open. What can I still do?

I have IOS 10.9.1

EDIT

Since the game won't open, there is also no starbound.log in the directory.

 

Try restarting your computer, then uninstall and reinstall Starbound.

 

In your starbound folder, go into the osx folder and run starbound manually and see what happens. If the process actually starts, then you *should* have a starbound.log created (look in storage_unstable).

They did a complete re-install already. Read the post.

 

Thank you very much, that solved the problem.
Before, I tried launching the application that was directly in the folder at "~/library/application support/steam/steamapps/common/starbound" and it didn't work, I launched instead the one in the osx folder and it works, although, when i try to launch it through steam, the same thing keeps on happening. For now it is not a problem, since I can play it directly from the folder, but I would still, in the future, would like to launch it from steam.
Is there any other way to fix it?

 

Steam not launching the game correctly is a known issue and has its own thread (which I can't seem to find right now but it's here somewhere, I know it).

Closing as OP has reported their problem was resolved (and the other issue should have its own thread already, if you don't find it either let me know and I'll re-open this one for other people to find).