The problem this post covers is the one associated with the macOS High Sierra 10.13.3 supplemental update for Mac. Some users of iMac Pro and some other Apple computers find it impossible to install this update. The primary symptom is having iMac stuck and frozen for a while after restarting it once the installation process is over. If it happens, and you are not the one to initiate the restart, you risk seeing a recovery screen telling that macOS should be reinstalled on the target disk. The worst thing about this situation is that you really have to reinstall macOS each time to access the system.
Most users who face such problem try to download the .dmg form the Apple’s official website manually. Is it really the only thing you can try?
A Few Solutions You May Try First
If you absolutely need the latest version of macOS High Sierra on your iMac, you should not give up. There are still several things one may try to solve the issue with upgrading.
First of all, a user should get the update on the App Store – exclude any other places. After a computer owner picks Restart when prompted, he or she may end up in front of the screen telling “The version of macOS on the selected disk needs to be reinstalled.” In such case, an update is a culprit.
The second thing to take care of before applying any updates is the safety of personal information. It is better to have a backup of all files in any case. Time Machine is one way to guarantee the safety of personal data. Copy the files to an external hard drive and partially to iCloud. If you are already running the process, do that in Recovery Mode. Only then go on with the installation.
You may either check the App Store for other available updates to avoid problems with this nasty one. One more idea is to switch between official Apple’s website and the App Store. Most probably, that is not the clue, but still, every possible solution is worth trying. Do not hurry to reinstall the operating system each time!
The smartest thing one can do in such situation is to contact official Apple’s support and explain the issue in details. Be ready to name everything: from the error messages you receive to the technical specs of your iMac Pro or another Apple computer. Most probably the guys will suggest that you should try one of the older updates of macOS High Sierra like this one. This time, the setup process will finish successfully. However, it does not necessarily mean that Supplement Update will do this time. Unfortunately, the DL1952 does not always solve the issue.
By the way, did you try to get rid of the firmware password? How about disabling FileVault encryption? If it still does not work, move to the best reply to this question!
What’s the Real Deal?
Be ready that it might take a while to try each method and discuss the problem with the Apple Support. Some users discovered that it is better to leave this suspicious, never-ending update in the Updates tab of the App Store.
You may waste a week or even more discussing things with the support and trying to figure out everything on your own. You will have to provide the support reps with logs and other details. Most probably, the answer will be something like that they have disabled the outdated iMac Pro update form the App Store. In such cases, the company releases new updates to solve the problem.