macOS Sierra Release Date September 20 Gallery macOS Sierra Release Date September 20 All News, Head, News macOS Sierra Release Date September 20 SWI Editorial Staff2016-09-10T18:49:01-07:00 Apple has announced that macOS Sierra, the next iteration of OS X for Mac computers, will be released to everyone for free on Sept. 20. The tech giant has also ... macOS Sierra Release Date September 20SWI Editorial Staff2016-09-10T18:49:01-07:00