After a fresh install of macOS Sierra, I installed the macTex distribution without any GUI programs. After that, I installed the latest release of the Tex Live Utility to update my tex distribution via a nice GUI. However, I cannot start the Tex Live Utility because macOS complains about that the program has not been signed by a verified developer. After I tried opening, there is a button under System -> Security to open the program anyway, but I keep going to see the same error message. This worked with another piece of software but with Tex Live Utility, this approach fails. Any idea on how to solve it?