Storyboard.storyboard could not be opened. Could not read the archive.
Please use a newer version of Xcode. Consider changing the document's Development Target to preserve compatibility.
I've received the above message when I tried to open the storyboard file of a new project that my collegue sent to me.
The proble is that my collegue used a newer version of Xcode and my version (4.2 the latest version working on Snow Leopard) is not able to open it.
And, here you are the workaround:
First of all, open the project ,containing your storyboard file, with Xcode.
Right click on the storyboard file and open as source code
In the source code modify the version from 2.0 to 1.0
Save the file
Right click on the storyboard file and open as interface builder
Now you can use it with Xcode 4.2, naturally you might have side effects, but for my pourpose this workaround worked fine.