If none of the above methods work for your Mac, you can try to clean install the macOS Sierra or High Sierra from external drive. After the restoration, try to install the macOS again. If you have a Time Machine backup, restore your Mac from the backup in Recovery mode. Choose Install a new copy of MAC OS and wait for the installation to complete.Restart the Mac again when this time, press Command + Option + R to get your Mac in Internet Recovery mode.Click Disk Utility and choose First Aid for your startup drive.Restart your mac and hold down the Command + R to boot your Mac into Recovery mode.This will help you to install macOS Sierra or High Sierra and newer versions, without data loss. The Mac will restart with options in NVRAM resetting. To reset the NVRAM on Mac, restart Mac and hold down Command + Option + P + R. NVRAM is a memory section on your Mac that store data like volume settings, screen resolution. If the Sierra or High Sierra installation is still won't complete in Safe mode, you can try to reset the NVRAM. When you Mac is in Safe mode, go to App Store and get the High Sierra update. To get your Mac into Safe mode:Īs you Mac start up, hold down the Shift key until the Apple logo appears. Install macOS in Safe ModeĪnother way to install Catalina, Mojave, Sierra or High Sierra successfully is to install the macOS in safe mode. If the installation get stuck when you try to update the Mac from Mac App Store, you may download macOS software from Apple website, which is the Combo updater which includes all the files required to update the macOS.

After the Mac reboots, try to install the macOS Catalina, Mojave, High Sierra again. Hold down the power button to power off the Mac. If you confirm that the installation is frozen, try the following methods to fix. Therefore, before taking further action, press Command + L, which will open the log file and shows you if the installation is still going on and the amount of time left. And forcing restarting a Mac during OS installation may cause data loss. So it doesn't necessarily mean that the macOS installation is frozen when the Mac stay at “20 minutes remaining” for two hours. Sometimes, it just takes a very long time for you MacBook or iMac to install the macOS Sierra or High Sierra update.

Troubleshooting macOS High Sierra Install Problems # 1.Check If the Install is Still Going on Calculating time remaining.' Here shows you how to confirm if the installation is still going on and how to complete the update successfully. If your macOS update also get stuck at 'Installation is in progress. The progress bar has been stuck at 40% or something, showing: 'Installation is in progress. After downloading the macOS installer, you try to install the macOS Catalina/Mojave, macOS Sierra or High Sierra but the installation get stuck. MacOS installation problem happens all the time.

Mac os sierra reinstall