Question: I installed the Xcode 6 GM seed, and I'm trying to create an IPA file for the first time. After archive success, when I click on the Export button, a window appears saying:

> 
> **Failed to locate or generate matching signing assets**
> 
> 
> Xcode attempted to locate or generate matching signing assets and failed to do so because of the following issues.
> 
> 
> * **Your account already has a valid iOS Distribution certificate.**
> 
> 
> If you have your signing identity on another Mac, you can import a developer profile. You can also revoke the current certificate and request one again.
> 
> 
> 

Here's a screenshot of the error:

![enter image description here](https://i.stack.imgur.com/XJOZQ.png)

Can anybody tell me how to solve this?

Answer: 
Only this way solved the issue for me:
Open the "Keychain Access" app and select "View" -> "Show Expired Certificates". Remove ALL expired Apple certificates! 
Restart Xcode.

See: Xcode unable to create distribution builds for App Store submissions or Enterprise apps -> <https://developer.apple.com/support/certificates/expiration/>
To fix this, I had to disable Automatic signing management in Target > General and import both dev and pro profiles after downloading them from my Apple dev account.
Rebuilt app and it worked, nothing else did. I guess this issue can come from many different sources.