Great title, eh? Surprise: this is another entry in stupid stupid stupid, and like the previous one, this too is brought to you by Apple.

The problem and symptoms: you’re trying to rebuild an iPhone app that another developer worked on in the past. <– important.

Let’s say the other developer’s name is “Bert Fiddlesticks”. When you build your app in Xcode you get a build failure with a message like this:

The identity ‘iPhone Developer: Bert Fiddlesticks’ doesn’t match any valid certificate/private key pair in the default keychain.

Workarounds:

First check this great page of workarounds on fixing iPhone code signing errors. It’s way better than Apple’s developer support pages on this same topic.
You’re back? Sorry that didn’t work out for you. Great page though, eh? Hopefully you tried changing the code signing entries in your project settings to get rid of Bert’s name. Me too. No joy.

Here’s what I ended up doing:

1. Find the project folder on disk.
2. Open the .pbxproj file with a text editor.
3. Search for Bert’s name. If you find it, e.g. in the code signing info section, delete everything between the quotes.
4. Save and close the .pbxproj file.
5. Restart xcode.
6. Go to project settings and change the code signing entries to your own name. Do this even if you already did it earlier.
7. Build clean and rejoice, for all should now be well.

  "CODE_SIGN_IDENTITY[sdk=iphoneos*]" = "iPhone Developer: Bert Fiddlesticks (ABC1232)";

I changed it to look like this:

  "CODE_SIGN_IDENTITY[sdk=iphoneos*]" = "";