libc++abi.dylib: terminating with uncaught exception of type NSException (lldb)

Solution 1:

CMYR - "his could also happen if you've wired up a button to an IBAction that doesn't exist anymore (or has been renamed)"

If you're running into this problem make sure that you go to Main.storyboard, RIGHT click on the yellow box icon (view controller) at the top of the phone outline and DELETE the outlet(s) with yellow flags.

What happens in instances like this is you probably named an action, then renamed it. You need to delete the old name and if that was the only issue will start right up in sim!

Solution 2:

Did you set the OS_ACTIVITY_MODE variable by any chance? To check if you have this variable set (and turn it off), in Xcode 9, do the following:

Select from Xcode menu Product -> Scheme -> Edit Scheme.. Select the Run scheme and look under Arguments. If you see the OS_ACTIVITY_MODE variable checked, deselect it