When macOS Big Sur first launched, many users had download issues when attempting to install it. Although Apple’s server problems have improved, certain Mac users are still facing problems downloading the most recent version.
If your connection isn’t great, you can experience download issues. Two of the frequent problems we’ve encountered are lost connections and sluggish download rates. If you are having trouble downloading the macOS Big Sur update, try connecting an ethernet wire to your Mac. This can help with some download problems and accelerate sluggish downloads.
If the issues still exist or you are unable to connect an Ethernet cable, try restarting your Mac and/or router. You should take your Mac to a location with a quicker internet connection if neither of those solutions works.