I am unable to add a new developer ID certificate. The add button is grayed out, my assumption is that you can't have more than 5 developer ID certificates. How can I delete an old developer id certificate no longer in use so that I can add a new one? The remove button is grayed out whenever you highlight a developer ID certificate. I can remove developer ID application certificates no problem though!
How to delete developer id certificate from account?
The Certificates Support Page indicates that you would need to contact the Developer Account Support team (or possibly request the removal by email to product-security@apple.com).
Phone numbers for different countires are here:
https://developer.apple.com/contact/phone.php
You can also contact them via Web Message here:
https://developer.apple.com/contact/submit.php
-Max
Did you visit KeyChain Access on your mac to be sure to clear out old there as well?