key chain warning The “System Roots” keychain cannot be modified [closed]

Just try below three steps

Step 1: Open your Keychain Access app.
Step 2: You will see list in left side as 'Login' ,'System' and 'System Roots', just drag your certificate in 'Login' option.
Step 3: You will get certificate install successfully in Keychain Access.

Step 1 - download your developer certificate and drop in into your DEFAULT keychain

step 2 - download apple WWDRCA certificate and drop into the same keychain.

step 3 - CHECK if there is a private key along with your certificate.(you should be able to see tiny triangle beside your certificate. Click on it to see if your private key is present or not)

step 4 - download the provisioning profile from the developer portal and drop into your xcode.

Try to do these things first. If you still get a error, then delete the extra apple certificates in your keychain and try the process once again.. it will do the trick...

I had the same issue when I tried to install an iOS push service certificate with the Keychain Access application opened, to solve this problem, I just closed the application, and double click the certificate, then the certificate was installed without any problem.