macOS Big Sur 11.2 update download failed error

Well one more way might be to reboot in Recovery Mode - Command + r - keys immediately at startup and connected via Ethernet. Presented with various option >> choose Reinstall macOS. This time, it was download the Full Installer 12.18 GB and attempt the installation. Some call this an In-place Installation. It should upgrade 11.1 to 11.2.

Strongly suggest doing a Time Machine Backup Before attempting and if doable - create a Bootable Clone to external drive as Insurance

Suggest - restart Router and then Shutdown Computer and connect via Ethernet connection. Restart computer in Safe Mode - Shift - Key immediately at startup. It does a Repair Disk, clears cache files and load only Apple Software - load slowly - Normal. Once in Open Apple Apps Store and find Big Sur and download. Try not to let computer go to sleep mode or Screen Save to activate. Be patient as one knows it Big Sur is 12.18 GB size. There are often periods where it seems to pause the download , normal be patient as countdown clock may say 15 minutes but in Real Time could be 30 - 45 minutes. This can and will happen several time in the process. If all goes well. it will successfully download and attempt to Launch. Do NOT allow it to start - Quist the Installer. Check Applications Folder for new App called Install Bug Sur. Make a copy to External Drive - future usage. Now, restart again in Safe Mode - then launch the Installer.

If this is not to ones liking and as last resort - Boot Safe Mode - Shift - Immediately and Open Terminal. Copy and paste this command  " softwareupdate -l " without quotation marks. This should List all available updates. Now, still in Terminal copy and paste this command again with quotation marks " softwareupdate -1 -a " - what was listed in previous command will start the download and attempt to install.

eelko208 wrote:

Also, I do not have a download in my Downloads folder (~/Downloads). Do not remember seeing a download there for any previous system updates either.

System install packages are not download to the Downloads folder. They are downloaded and run from the Applications folder. So look in there to see if there's a Install macOS Big Sur.app file in there. If there is delete it.

Then boot into Safe Mode according to Start up your Mac in safe mode - Apple Support , go to the App Store search for and download Big Sur. Then run the installer while still in Safe Mode:

NOTE: Safe Mode boot can take up to 10 minutes as it's doing the following; 

• Verifies your startup disk and attempts to repair directory issues, if needed

• Loads only required kernel extensions (prevents 3rd party kernel/extensions from loading)

• Prevents Startup Items and Login Items from opening automatically

• Disables user-installed fonts 

• Deletes font caches, kernel cache, and other system cache files

Issue Resolved: I have Kaspersky Internet Protection as my AntiVirus/etc. There's a difference between Pausing protection and removing the app to get the install to work. Pausing the protection, my download and install would fail every time. After Uninstalling the AntiVirus App and rebooting the system, the download and install worked perfectly. Then I just reinstalled the App. Not a perfect solution, but workable and I am okay with this. Booting into safe mode was not an option for me.

I hope that this helps.

Hello Tigrosso,

Thank you for using Apple Support Communities!

We understand from your post that after clearing space on your laptop you are still unable to update the software due to an error saying that the download failed. Look for an installer in the downloads folder and put it in the trash. Then try downloading the update again. If the issue persists, try reinstalling the current software using macOS Recovery and then downloading the update again.

How to reinstall macOS - Apple Support

Best Regards.

The error message in picture explains everything - Internet Connection is either not working or is too unstable / slow to download the update reliably. Suggest restarting the Wifi Router and then restarting the laptop in Safe Mode - immediately hold Shift Key at restart. Disconnect all other devices using the Wifi - this will give the max bandwidth to laptop. Once logged in the computer will function slower - Normal. Try the download again.

David_MofU wrote:

Issue Resolved: I have Kaspersky Internet Protection as my AntiVirus/etc.

First, there is no reason to ever install or run any 3rd party "cleaning", "optimizing", "speed-up", anti-virus, VPN or security apps on your Mac.  This user tip describes what you need to know and do in order to protect your Mac: Effective defenses against malware and other threats - Apple Community.  

There are no known viruses, i.e. self propagating, for Macs.  There are, however, adware and malware which require the user to install although unwittingly most of the time thru sneaky links, etc.   

Anti Virus developers try to group all types as viruses into their ad campaigns of fear.  They do a poor job of the detecting and isolating the adware and malware.  Since there are no viruses these apps use up a lot of system resources searching for what is non-existent and adversely affect system and app performance.

There is one app, Malwarebytes, which was developed by a long time contributor to these forums and a highly respected member of the computer security community, that is desshoigned solely to seek out adware and known malware and remove it.  The free version is more than adequate for most users.  

Also, unless you're using a true VPN tunnel, such as between you and your employer's or bank's servers, they are useless from a privacy standpoint: Public VPN's are anything but private.  

For what it's worth a while back the government banned Kaspersky software from it's computers as it was to insecure. That and the fact that it's worthless for Macs is good reason to uninstall it.

I have already filed a radar (if more people would do so it could maybe force Apple to take a serious look into it). My log files indicate that the issue is after downloading, at the validation phase. Some people suggested that the hdd could be failing but SMART doesn’t indicate something that could support that. Take a look at install.log or the output of softwareupdate -i -a

https://discussions.apple.com/thread/252538700?page=1

https://discussions.apple.com/thread/252527368

More examples of AV interfering in operation of OS and solutions

Amen. I finally got 11.2.2 to install by depriving my whole house of internet, downloading the 2.3GB file with the router's ethernet cable plugged via adapter directly to my Macbook, booting safe, and waiting. What a crock! Amateur hour from a multi-trillion dollar company. This should not be happening whether I use ESET or a VPN or anything else. It's just lame.

Yes, ESET. I don't remember ever having to disable it prior to Big Sur and haven't yet. Ugh, if that's the issue.

You can report the issue here: https://feedbackassistant.apple.com/ or by using the Feedback assistant app. See more details here: https://developer.apple.com/bug-reporting/

I'm now two-for-two on successful upgrades...I boot Safe, ensure I have a maximal connection--20mbps seems to be enough--and leave it alone, returning after a couple of hours to a login screen and upgraded computer. Suboptimal experience, to say the least. My experience implies a connection between connection speen and choking but I tried one with a gigabit connection and it also hung until I booted safe and tried again. When it fails, there's one process that pegs cpu in Activity Monitor at 100% and ignites the roaring fan...it appears to be a crashed process and so I kill it and all goes back to normal. I can't remember the (very long) name of the process...

It appears that the error is misleading. Several people have reported the same issue, including me after unsuccessfully tried everything Apple support had to offer (sans reinstall) like different networks, disk repairing, safe mode.

Same problem. Retried several times. Why they don't retain the download cache so we don't have to re-download the entire 3.25GB from the beginning each time is beyond me. The problem is NOT the internet connection. All the "solutions" I've seen so far on this forum are work-arounds (hacks). Apple needs to fix this ASAP. It took me several attempts and a lot of freeing up of disk space to get Big Sur to install in the first place. Now the thing can't even update itself, despite my MBP having plenty of free space. I don't want to reboot into safe mode, stand on one foot, pat my head and rub my belly. I want an updater that A) works or B) at least provides accurate error messages. If I'm going to pay more for a product, I expect it to work at least as well as the competition.