Possible Duplicate:
Codesign error: Certificate identity appearing twice
I am getting this error.
Certificate identity 'iPhone Developer: tobias diestelkamp (PXVT443VS6)' appears more than once in the keychain. The codesign tool requires there only be one.
Is it possible that this error occurs because of expired certificate?? I dont know my certificate is expired or not..
It means you are having more than 1 certificate with same name in keychain. Just delete the old one and keep the new one installed. If it does not fix the problem delete all the certificates of that particular name, install a fresh one and restart the xcode and mac. I was having the same problem and this procedure helped me. Hope you will get helped also.