My 15" MacBook Pro (Retina, Mid 2012) is running slowly since I attempted but failed to install Security Update 2019-003 High Sierra. After researching the problem, I discovered a number of reports indicating the update has failed other users and quickly decided I will wait for Apple to release an "updated" update. However, since attempting the failed install, my machine is running so slowly I can hardly use it. It's as if it's trying to move "under water". Something as simple as moving a document to a different folder stalls the machine as does opening a Web site. I've tried rebooting to no avail and testing the speed on my IP. I know enough about my Mac to realize that I know very little and am terrified to start opening folders and deleting things without advice from someone who knows what needs to be done. Now that I've revealed that I am a complete computer dodo, I hope not to embarrass myself further. History: I received an automatic update from the App Store that a restart was needed for Security Update 2019-003. However, when I clicked restart, my MacBook Pro changed to a black screen with only the cursor showing. The next morning nothing had happened and the only option I had was to do a hard shutdown and restart. When I saw the upgrade had not been installed, I continued after making room on my disk. After several failed attempts, I found information that the update had failed other users with the same circumstances that I encountered. My problem is that I don't know how to clear out the portion of the upgrade that is there and ready to install, that I believe is causing my machine to run so slowly. I've searched many times and ways but can find nothing on how to remove what was downloaded and pending installation after restart. Does anyone know where I can locate this on my Mac and how I can rid it from my life? The upgrade is obviously flawed and I just want it trashed from my machine. Any help is appreciated. Sincerely, Kathryn

  • you can reinstall High Sierra which may be easier than undoing what has been done.
    – Natsfan
    Commented Jul 21, 2019 at 4:29
  • JMH, thank you for your very logical recommendation and comment. Is a reinstall difficult for a dodo to do? Will it cause a loss of my personal folders or files (other than the one I want to lose)? Would it be better for me to do a restore from Time Machine before this happened and how do I keep it from happening again? I have removed the checkmark authorizing automatic updates from the App Store. Commented Jul 21, 2019 at 5:05

1 Answer 1


Well it looks like following this should resolve the issue but its not for the faint of heart...


Unfortunately the issue doesn't appear to be simple.

Using terminal and running these commands seem to reset the update so it quits trying to install on shutdown.

sudo rm -f /Library/Preferences/com.apple.loginwindow.plist
sudo rm -f /private/var/db/.AppleUpgrade
sudo rm -f /private/var/db/.SoftwareUpdateAtLogout
sudo reboot

Black Screen With Cursor on Logout in Yosemite

  • Oh, dear God. Thank you for the link and you're correct, it's not for the faint of heart. I wouldn't know even the first thing to open or do when following these instructions. Fortunately, I have Time Machine that backs up regularly. Should I go back a week or two and restore before this all began? How would I know what date the download took place to restore the day before that? I think I might be in Hell with this failed upgrade. Commented Jul 21, 2019 at 5:01
  • Unfortunately time machine does not touch OS updates so that shouldn't affect it. Commented Jul 21, 2019 at 5:22
  • So doing a reinstall of High Sierra may be the best choice. I've been reviewing the process and found a reinstall can be done without losing data. But if I chose this type of reinstall, would it remove what I want removed? Commented Jul 21, 2019 at 6:04
  • It should remove updates and get you back to the version that was released without affecting your apps or data. Commented Jul 21, 2019 at 6:24
  • Based on the description that I provided initially, do you think the problem is what I assume in that the download that did not install is bogging down my system or could it be something else that I should consider? Commented Jul 21, 2019 at 6:29

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