Mac error after update
Although macOS is a very robust operating system, system updates can sometimes be problematic. In my case, the progress bar stopped and stayed like this for a few hours. If you're having a Mac frozen during the system update, here are some ways to back up your data, tackle the problem, and fix it.
Install the Update in Safe Mode
If it’s clear that your Mac update isn’t going anywhere, then hold down the power button to turn off your Mac. Once you’ve done this, boot your Mac into Safe Mode. There are several ways to do this, but the simplest is by holding the Shift key as it’s booting.
The Apple logo should appear on your screen with a loading bar, and after that you should boot into Safe Mode. From here, run the macOS update as you normally would to install the update – hopefully without a hitch.
Check the Apple Systems Status Page
One very quick and easy thing to do that could save you a lot of hassle with secure updates (or other faulty Apple services) is to go to the official state systems page. Here you will see the status of almost every Apple service you can think of. Examine the status of "MacOS Software Update" to see if the update servers are working properly. If the bubble is green, then everything is fine and the problem is elsewhere. If it is red or yellow, then you will have to fix the problem until the servers return to normal. Speaking of sitting …
Sit it Out
It's as painful as it sounds, you can let the Mac sit for a few hours and see if it's really frozen. Sometimes the update could be stuck in a lull but not completely frozen. Some update processes will take much longer than others, resulting in a seemingly blocked progress bar. We can verify that the system is still being updated by pressing Command + L to display the estimated installation time. If this does not appear, let the update sit for a while. Some users reported that their update took more than ten hours. Have a coffee, do some other work, shop, do all you have to do to save time and let your Mac do its job. Large system updates (sometimes) take a lot of time!
Refresh the Update
If you are sure that the installation is actually frozen, you will need to follow the following steps, and the following steps, one after the other, until the problem is resolved. Let's try to give a little help to the installation by refreshing it. Hold down the power button and wait about 30 seconds. When the Mac is completely off, press the power button again and hold it down. Now the update should resume. Press Command + L again to see if macOS is still being installed. If it is useless, go to the next solution below.