please look at the following screenshot
![enter image description here](https://i.stack.imgur.com/Ts0JJ.png)

As you see there are two certificates. All are mine, with maching user's ID and common name.

Whenever I build the application and launch it in Xcode for device I receive the fatal, that this certificate is duplicated. So I delete the expired one and launch the application again - it's being installed and debugged on device without any problems.

But when I launch other project or reboot that expired certificate is shown in the keychain again and again and it's becoming a little bit annoying.

What causes that the expired certificate is being readded to the keychain? How can I dissable it?