Info.plist, Failed to launch simulated application: unknown error

I downloaded an opensource iphone project. Failed to build it.

The error message is

could not read data from '/xxxx/xxxx/xxxx/Info.plist': The file “Info.plist” couldn’t be opened because there is no such file.

I see, it's the problem of Info.plist. I removed the wrong path and leave it blank in the build setting. It then turned out to be a mystery "unknown error":

Error from Debugger: Failed to launch simulated application: Unknown error

The app build successfully, simply don't run. And xcode shows no hint to solve this problem.
It could be a serious problem if you empty the "Info.plist file" in build setting by mistake.

To solve this problem, simply set "Info.plist file" to "Info.plist" or the actual name of your info.plist in your project.