So: I got a new Mac. I went to the developer provisioning portal, then revoked my certificate. I created a new one.
Now whenever I open XCode it complains that I have duplicate developer certificates. And yes, when I check with Keychain, there are two. I then delete the oldest one, but XCode is apparently very much in love with the old one: It keeps recreating it.
What to do?
Answer here: Xcode could not find a valid private certificate/valid key-pair for this profile in your keychain
Short version: Delete all certificates from your keychain. Delete all provisioning from XCode via the Organizer. Request and generate new certificates in the iOS provisioning portal. Download the new provisions and import them into XCode by doubleclicking. FInally, go to your project and make sure that the right signing is selected, just to make sure.
