I have downloaded the upgrade from 10.12.6 to 10.13 three times and each time the computer restarts, nothing has changed. It simply refuses to install and gives me no clue as to the reason why. I am on a late 2013 27" iMac with 24 gb of memory. The one possible cause is the continuing glitch in the OS that continue to reload my LaCie external drive used as TimeMachine, even though I have ejected it.
iMac (27-inch, Late 2013), iOS 8.1.2
Disconnect the external drive and try again. If High Sierra does not prompt you to install double-click on the installer to open it. If that doesn't help try doing the install in Safe Mode:
Use safe mode to isolate issues with your Mac - Apple Support
Disconnect the external drive and try again. If High Sierra does not prompt you to install double-click on the installer to open it. If that doesn't help try doing the install in Safe Mode:
Use safe mode to isolate issues with your Mac - Apple Support
Thank you. Booting into safe mode solved the problem. I still have no idea what was blocking this update, but your solution solved it. Much obliged.
iMac 2013 will not install upgrade
