There's a reason why you can't rate Sierra on the Mac App Store: because it is crap.
Never before have I had so many problems with an operating system as with this one (Mac Pro Late 2013).
- 4K monitors are not being recognized on boot up
- display errors
- network drives are no longer automatically connected to
- Safari restarts without rhyme or reason
- exceptionally slow performance
- USB drives disappear
- loads of software suddenly stopped working (did they disable Rosetta again? WTF? How about a bloody warning?)
- annoying "UPDATE!!!!" feature, which resembles Microsoft "sales techniques", more like pimps asking for money
I will never, ever update my computer again, once I get this system working. Keep the next bloody OS, it's not worth it anymore. I need a machine that works, not a Windows computer with an Apple logo and a buggy macOS.
And for the forums at Apple "Apple is not here": that's bloody BS, because Apple knows what is happening in their forums, who else would close other people's (never mine so far) forum entries when those get to become flame wars about Apple products? I am glad there are forums like macrumors, where we can still show that we DO LOVE Apple, but at the same time, we hate what it has become.