code signing identity <name> does not match any valid, non-expired code-signing certificate

I'm hoping someone can help me reso开发者_如何学Clve this maddening issue. My friend and I are developing a mac store app, hosted on github. We published the app a month ago from his machine, with his dev center account. I recently pull the source from github onto my machine, to work on an update, but when I try to build it in xcode, I get the error:

"code signing identity does not match any valid, non-expired code-signing certificate in your keychain"

I downloaded the 2 certificates from my friend's account on the dev center and put them in my keychain, along with the general apple certificate, but I still get the same error. Is there a private key issue here? I am not sure why I even have to sign the code? All I am doing is trying to build it and run it in xcode. Any help would be much appreciated.

Change your build to Debug or Release.