imac freeze while updating to mac os 10.14
open app store -> update mac os mojave -> accept agreement -> processing install -> freeze, mouse and keyboard can not move.
iMac Pro
Try booting into Safe mode
<http://support.apple.com/kb/ht1564>
This will not load any 3rd party additions, it will load some more conservative Apple drivers (may cause screen flicker), and it will clear some kernel caches (a cache is saved data in a form that can speed up a program, but is totally redundant to the original source, and thus can be safely cleared). Booting into Safe mode is just an experiment, but can frequently eliminate any 3rd party interference, or a cached item out-of-sync with the world. (Verify Safe mode via Applications -> Utilities -> System Information -> Software -> Boot Mode -> Safe vs Normal)