MAC OS SIERRA
Hi, like usual, I have upgraded to the next free Mac Os update - OS SIERRA. Then, now, I cannot open my iMac! I have a relative with the same probelm, his Macbook was updated to the same OS, and now he cannot open it. WTH Apple?!
Wha are we supposed to do now??? Anybody please help!
iMac with Retina 5K display