In case you tried to download mac OS Big Sur today and got the message: "Installation Failed: An error occurred while installing the selected updates", you are not alone. It turns out nearly everyone who has tried to download the new mac OS has gotten the same message and has been unable to download it. Apparently Apple's servers are down and they're in the process of getting it fixed. 

macOS Big Sur is a big deal in that it is the first macOS to leave OS 10. It’s predecessor macOS Catalina, which I’m currently running, is OS 10.15. Big Sur is 11.0. macOS Catalina helped make the transition to 11.0 by dropping 32 bit apps and only running 64 bit apps. 

One more detail on macOS Big Sur is that Apple delayed its release by quite a bit. Catalina was released October 7, 2019, Mojave was released September 24, 2018, High Sierra was released September 25, 2017, and Sierra was released September 20, 2016. As you can see, a November 12 release date is significantly delayed from the typical early fall release dates that Apple tries to follow. It seems as though Apple had more bugs to iron out with this new OS and then combined with everyone trying to download it at once, we have the mess that we do now. 

Anyways, if anyone is able to get it to download, feel free to comment below. I’ll let you all know what else I find out and when I’m able to finally get it downloaded. The YouTube video I have linked below is what confirmed to me that it wasn’t an issue on my end. You can also check there for more updates in the comments section as well. 

Update: My Mac has begun to download the software. I’ll keep you all posted on my progress.

You are brave. I'm still on Mojave because i'm nervous that some of my favourite apps won't work in 64bit.

I liked Mojave a lot! One thing you can do is do some research into what apps are supported in 64 bit and which ones are not. There should be plenty online to answer that question now.

I was worried about jumping to Catalina last year because of that. I had music files I didn’t want damaged. I downloaded the 64 bit garage band on Mojave first, updated the music files, and then jumped to Catalina. My sister jumped to Catalina before she updated some music files and when she tried to open, they thankfully updated to the 64 bit version so perhaps my fears were overrated.

But, I do understand the hesitation. Fortunately for me, I’m more of a simple user that writes articles and watches YouTube. I don’t have a ton of apps that I use. Just know that when/if you make the leap, there are plenty of resources available to help you navigate your understandable concerns about 64-bit apps.

I refuse to upgrade my MAC because I need 32 bit support.

I’m long past the point where my computer can be updated (2008 Mac Pro) so no worries here.

Update: I got it downloaded and am now in the installation process. 👍

This is my first post on macOS Big Sur. I made it to the other side, y'all.

One quick note: Something I did was I made sure to not let my Mac go to sleep as the downloading process was happening. I tried that the first time and as a result I had to redownload Big Sur.

But by not letting it sleep the second time and seeing it all the way through, I was able to get it downloaded and from there, install.

So far everything seems to be working fine except for the messages app. That isn’t loading. I sent a report to Apple to let them know. Other than that, everything is working. I’ll let you all know what other issues I come across (if any).

I tried messages one more time before I shut out for the night and the app is now working fine. So, in case any of you who upgrade notice the messages app not responding at first, just give it a little bit of time and you should be good.

I downloaded and installed Big Sur on my 2013 MacPro trash can Saturday Nov 14, evening . It is about a 12.8 Gb download, and took about 45 mintures during the dinner hour. It then took about ~45 minutes to install, rebooting several times. The first attempt at installation locked up on a restart step - so I had to finally turn the machine off, and restart it manually, but after that everything seemed to flow properly.

All the native Apple apps seem to work, iMessage particularly works just fine.

I haven't tried Adobe's software yet, as I don't use that on this older device any longer.

Maybe Safari seems a bit snappier.

I did make certain I had two seperate external back up copies of my boot drive before begnning. Never replace an operating system without a reliable 100% funtional back up copy of your existing boot drive. You might find you need it - I didn't this time, but I have needed my back up drive more than once over the years with an OS upgrade.

edit -> I have subsequently added Big Sur to my just recently repaired ( by Apple ) 2019 13" MacBook Air, and it downloaded and installed smoothly and without issues.