Nikon Japan has released a product advisory warning that images may be corrupted when using Nikon Trasnfer 2 with View NX-i. See below for the Google translated version of the Nikon announcement.
Thank you very much for your continued patronage of Nikon products.via Nikon RumorsIt turned out that image data may be corrupted when transferring images using Nikon Transfer 2 on macOS Sierra version 10.12.2 in our software "View NX - i".
ViewNX-i Ver.1.2.4 which was released on November 22, 2016 supported macOS Sierra version 10.12, but since it was not designed for macOS Sierra version 10.12.1 or later, we are currently working on compatibility.
For this reason, until compatibility with macOS Sierra version 10.12.1 or later can be confirmed, and please do not use Nikon Transfer 2 until an announcement from us.
We are diligently working on a solution for this phenomenon and we will notify once a fix has been issued.
We appreciate your continued patronage of Nikon products.