macOS upgrade question

DaveWT

Well-Known Member
OK so the update to Big Sur came out yesterday (Thursday Nov. 12). Today (Friday Nov. 13) I did the update. While this was going on I pondered these settings and not sure I really understand what their affect is...

Screen Shot 2020-11-13 at 10.52.02 AM.png

Notice that I had selected "Download new updates when available" (which clearly they were available for a full day) but I had not selected "Install macOS updates". I had assumed that meant then when an update became available (like the Big Sur update) it would automatically download that update and just keep it ready on my system until I chose to actually start the update. But actually, today when I started the update process it had to download the whole update.

Screen Shot 2020-11-13 at 10.52.20 AM.png

So what do those settings really mean?

Since the first screen shot was taken I have also checked off the "Install system data files and security updates" box, thinking that is something that sounds like it should be done automatically. What is the "good advice" on these settings?

Of course, before doing the Big Sur update I did a complete Carbon Copy Cloner clone backup and checked the Time Machine had also done a recent backup.
All appears fine so far...
 

chas_m

Well-Known Member
First let's clarify for the benefit of others reading this that this entire discussion applies ONLY to Apple system updates, nothing else.

The options referenced in the first screenshot mean pretty much what they say. Checking for updates (by itself, periodically) lets you know if one is available, but does nothing about it without you taking action.

Download new update will take the extra step of downloading updates, but does not install them automatically. It will only download updates when the computer is not in use (asleep), Power Nap is turned on (for Macs), it is charging and is connected to Wi-Fi -- and has enough free space to download the update.

Likewise, the "install macOS updates" will do exactly that automatically under those same conditions as above. It may ask for owner credentials (login password or Apple ID if it hasn't been verified in a while), but otherwise will go ahead and do the updates overnight when the computer is not in use.

Finally, the option to install Mac App Store update automatically is the same as above, except that it applies to software from either Apple or other developers that you got from the Mac App Store.
 

DaveWT

Well-Known Member
So if I understand you, having the first two boxes checked should mean that the Big Sur update should have downloaded overnight once that update became available. (I do have Power Nap enabled and the other conditions you stated are all met.) Then later the next day when I told it to go ahead and do the update, it should have the update software already there and not need over 43 minutes to download it. But that is not what happened.
 

chas_m

Well-Known Member
I think it did update the software, but once you start the upgrade process it then verifies the download, which may result in some additional downloading if something's not right. That said, 43 minutes sounds about right for a MAJOR upgrade from an already-downloaded installer. A huge number of applications got updated as well as the system for Big Sur, since everything's a "universal binary" now. This will take considerable time and require **A LOT** of free space to accomplish, so unlike routine system updates the upgrade to Big Sur should be expected to take up to two hours, depending on things like the age of the machine, type of drive in the machine, and yes internet speed.
 

DaveWT

Well-Known Member
Wow, I heard the update was big but I had no idea it was that big. I will stop questioning my settings now.
 

chas_m

Well-Known Member
Having just updated to Big Sur this evening finally (rule #1 -- DO NOT do a system upgrade until a big project is finished, and not before you've made backups!), I can confirm that the update took about 30-45 minutes (wasn't watching closely) on my MacBook Pro.

LOVE the new look!
 
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