iMac 27" 5K Late 2015 screen artefacts on shutdown
Bit of an odd one - upgraded to Mac OS Sierra, all working fine. When I shut the iMac down, the whole screen displays weird artefacts - (graphics glitch?), then shuts down fine. So not causing a problem, per se, but wondered if anyone else has had this issue?
iMac (Retina 5K, 27-inch, Late 2015), macOS Sierra (10.12)