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iMac will not restart cleanly  



iMac, mid 2011, 2.5 Ghz, running 10.13.6

The mac will not restart cleanly.  When I reboot, from command line, from the menus, from any way I can imagine, the apps shut down, the screen goes black and I am left with a cursor on the black screen and it never restarts.  I have tried a pram, svram, and whatever thing I can imagine and it still is the same.  I have a security update that will not apply due to this inability also.  I am force to hard power off the mac, and restart with the power button.  Then, things work for awhile.

Any help is appreciated.  I also have a weird wifi issue that I will post as different question.  (Could they be related?)





1 Answer

Boot into Safe mode and try to reboot while in Safe mode

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)