code-signingiphoneobjective cxcode4
CodeSign error: Certificate identity 'iPhone Developer: XXXX (12345678)' appears more than once in the keychain. The codesign tool requires there only be one.
So I go to my keychain and delete it. But I get this error every time I restart Xcode 4 and some app is adding the expired old certificate back into keychain. Any ideas why and which app?
The fix is pretty simple. In the Build Results window (which you probably got to by clicking the error icon in the lower right corner of your project window), change the pulldown menu from ‘Device - iPhone xxx’ to ‘Simulator - iPhone xxx’.
(source: kickasslabs.com)
This happens if you forgot to change your build settings to Simulator. Unless you want to build to a device, in which case you should see the other answers.
Best Answer
I just had the same problem. It has been fixed. It came after I submitted an app and installed a few certificates to sign the app.
Quick Fix: Open up KEYCHAIN ACCESS > click on MY CERTIFICATES> in there you will probably see iPhone Developer: . You will probably see it TWICE! Select the one with the earliest Expiration date, right click and select DELETE.
Restart Xcode if you haven't. Works now. :)
Happy Coding.