Big Sur spends hours downloading and then gives an error on both of my Macs.

I agree. Best to wait a bit for traffic to decrease. Also, the download can take up to an hour, more or less, then another 40 minutes to load, more or less. Be sure to use a wired Ethernet connection, not Wi-Fi, as wireless downloads of large operating system files will often get corrupted and then either not load or will have issues.

RonK6XC wrote:

How do I fix the error after downloading Big Sur to my Macs? (Mac mini and MacBook air

You do an update at a later time, when traffic dies down.

Apple's servers are getting flooded. Try again in about an hour.

If you're able to download it to one computer, make a copy of the installer instead of redownloading it on the other.

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