Question: An app extension is causing a code signing issue. This app is already on the Appstore (with this extension) yet overnight for some reason when I have come back to this app im getting![enter image description here](https://i.stack.imgur.com/jsrhn.png)

A strange error as its contradicting itself by showing two exact identical certificates in said error message.

Ive tried 
clean and restart, deleting derived data, regenerating provisioning profiles, deleting and creating new profiles. using both xcode 6.1 and xcode beta and [This](http://aplus.rs/2014/embedded-binary-is-not-signed-with-the-same-certificate-as-the-parent-app/)

I have also searched SO [Xcode6:Embedded binary is not signed with the same certificate as the parent app](https://stackoverflow.com/questions/25927604/xcode6embedded-binary-is-not-signed-with-the-same-certificate-as-the-parent-app) and no solutions offered worked

(Deleting the app extension removes the error)

Answer: 
I have tried the following solution is working this morning! Please try it!

> 
> The only solution here was that I went to Developer Portal, removed
>  all profiles, then removed all downloaded profiles through Finder, did
>  Clean project and Clean Build folder, closed and re-opened Xcode. 
> 
> 
> Then I opened my project, went to both app and extension targets - at which
>  point Xcode realized no profiles are present and thus goes to
>  Developer Portal to get them. Since there’s nothing to download, it
>  goes through each App ID you have on your account and creates
>  development profile for each one.
> 
> 
> 

<http://aplus.rs/2014/embedded-binary-is-not-signed-with-the-same-certificate-as-the-parent-app/>
I had the same issue. This started on the day when my Certificate got expired after a year. Following steps worked for me:

1. Delete the old expired certificate from Keychain(You will be able to see a red cross on the certificate icon)
2. Restarting your mac