The steps for this are quite simple and is a great alternative to try, especially if the Software Update servers are congested. Thankfully, you can also get the new macOS version from the Mac App Store itself. You don’t have to limit yourself to just installing the macOS Big Sur through the Software Update window. Hopefully, that helped fix your failed installation of macOS Big Sur. The process from there should be pretty intuitive. Thankfully, if this does work, then simply wait for the 12GB of files to finish downloading.

That should be all you need, go ahead and click on Upgrade Now so you can try and install the macOS Big Sur update.

Once you’re there, press the Command + R keys together to refresh your Software Update window.

Now, go ahead and click on Software Update.

Start by opening up the Apple icon on the top-left corner of your screen and select System Preferences.

Here’s how you can refresh the Software Update window on your Mac: This might help you avoid congested servers by having your Mac connect to a less populated server. We suspect that by refreshing the Software Update window, perhaps this refreshes your connection to the Apple server as well. Thankfully, this is pretty easy to do and should be a straightforward fix to this annoying problem. Before installing the update, a lot of users have found success in refreshing their Software Update window.

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