11-19-2015, 12:43 AM
It's either not really a zip file or it's corrupt. It's weird, but the Archive Utility will compress any file that it can't unzip.
My guess is that the original file was simply renamed. Go back to the original zip file and rename it to end in ".numbers" instead of ".zip" and see if the file will open in numbers.
My guess is that the original file was simply renamed. Go back to the original zip file and rename it to end in ".numbers" instead of ".zip" and see if the file will open in numbers.