This problem is mainly caused by DUPLICATIONS:
1> duplications of .m Files
goto TARGETS->Projiect->Build Phases->Compile Sources >
check duplicated .m files, keep one and remove others.
2> duplications of variables’ names
check all your variables defined throughout your project >
change duplicated names.
GOOD LUCK 🙂
When you get a new macbook pro, as the apple developer, we need to prepare the things below in order to keep on coding in this new computer.
1> Download all provisioning files
In your new computer > open Xcode > Preferences > Accounts > login your Apple ID for your projects > once logged in click “View Details” on the bottom right side > once loaded all the info click “Download All” on the bottom left side > 50% done.
Lastly, we need to transfer all corresponding certificates with “Keychain Access”
2> Export keychain items from your old computer (“Keychain Access”)
Select “My Certificates” from the left side panel
Select the items you want to export in the Keychain Access window.
Choose File > Export Items.
If the Export Items menu is dimmed, then at least one of the selected items can’t be exported.
Select a location to save your keychain items, click the File Format pop-up menu, then choose a file type.
Enter a password.
The password is required to access the exported keychain items when you import them on another computer. Some exported items, such as public keys, don’t require a password.
3> Import keychain items into your new computer (“Keychain Access”)
Choose File from Menu > Import Items.
Navigate to the keychain items file you want to import and select it.
In the Destination Keychain pop-up menu, choose the keychain you want to import to, then click Open.
And there you go! Remember to reopen your Xcode.