Apple released macOS Sierra on September 20th, 2016. Some customers have reported issues installing FXpansion software on Sierra, which we have now reproduced.
We recommend that you do not install this update until we update our installers to be fully compatible. If you have already installed Sierra, instructions on how to run the installers can be found on our forum here
FXpansion software is tested and compatible with released versions of Mac OS X 10.9 Mavericks, 10.10 Yosemite, and 10.11 El Capitan. Pre-release and beta versions of Mac OS X / macOS are not supported.