If you’re having DNS issues, you may want to check to see if custom DNS has been set on the Mac (or at the router level), or if your ISP DNS servers are offline. In either case, make sure the Mac is online, and easy way to do this is by opening Safari and going to a great website like and make sure it loads and works as expected. Some Mac users have encountered the Installation Failed error because their Mac has dropped an internet connection, or because of a DNS issue. Make sure the Mac is online and functionally connected to the internet Sometimes simply rebooting the Mac and trying again can resolve the failed installation error. This is particularly relevant if the software update you are trying to install is brand new, like a major system software release (this happened with Big Sur for example). Users may encounter failures to download and install macOS updates when Apple servers are overloaded, therefore sometimes simply waiting a bit can be helpful. We’ll go through a variety of troubleshooting steps, as well as offer an alternate solution to download macOS installers even if the System Preference panel for Software Update is repeatedly showing failure errors.

Troubleshooting macOS “Installation failed, An error occurred while installing the selected updates.” Errors There are a variety of reasons Mac users may see the “installation failed” error when trying to download and install a particular MacOS software update, and we’ll go through some troubleshooting steps to help resolve the issue here.

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