Mac froze during update to Big Sur 11.6 from 11.5.2. I hurried to cancel and close everything. Can I keep version 11.5.2. until the version following 11.6. is ready and tested?

The macOS 11.6 update works fine. However, you should ALWAYS BACKUP before installing any updates.

Time Machine is the easiest and most pain free method to backup a Mac. You just need a large enough external USB hard drive, typically 2-3 times larger than your internal drive. Connect the drive, answer YES to the question about using it as a Time Machine drive and then wait for the first full backup to occur. After that, so long as the backup drive is attached it will backup any changes every hour. When not attached, macOS will snapshot the changes to the APFS file system and when you attach the Time Machine drive it will backup the snapshots then remove them from the internal disk.

Alternative 3rd party backup tools include Carbon Copy Cloner or SuperDuper! or cloud based backup services such as Backblaze, etc.

An update should not freeze, but you may have some software installed that is causing a problem. Happy to help you diagnose the problem but you should make a backup first. It's possible the update just takes a long time to install. If it takes more than a couple hours and is still frozen then it is certainly stuck.

For security reasons, it is extremely important that you update to 11.6 as soon as you can. The update contains security fixes for a very nasty remote exploit. The vulnerability means a malicious text message or email can hack your Mac without any action on your part. You do not even need to click the malicious link. This hack is in the wild and in active use by various nation state governments but now the cat is out of the bag and anyone can potentially use the same vulnerability. The faster you update the safer you will be from malicious attacks.

Is this a MBA Intel with a tiny 128 GB Internal SSD ??

Is this the MBA Apple Silicon M1 which will have the larger 256 GB SSD ??

How much Empty Space is on the Drive before attempting the update to Big Sur 11.6 ??

Are there any AntiVirus, Disk Cleaner, Optimizers, Un-installers, etc installed which should be removed as per Developers Instructions. They are useless, unneeded, cause havoc and interfere with the normal operation of the OS and may even Corrupt the OS requiring a Reinstallation. The Built-in Security of Big Sur is all that is required.

Any of the above mentioned will interfere with the update process.

It is too bad that many times when Apple does an update to address one issue they create others. With 11.6 came new issues along with the Safari 15 update as well. I feel many of the updates that Apple deems important are more focused on business users and not normal consumers. I'm never in a rush to update until I see what new issues develop.

Hmm, I work in IT supporting Macs and our perspective is the opposite. We feel Apple cares more for the retail users than the business users. They are constantly making design decisions that force us to scramble to adapt. Such as all the security changes from High Sierra to Big Sur. Although we welcome security improvements, they kept breaking vendor security endpoints and we had to wait a year or more before we could upgrade the Mac users to the latest macOS. We currently run at least a year out on macOS releases as a result. Meaning we are still on Catalina but plan to make the jump to Big Sur soon just as Monterey is about to be released. We won't get to Monterey for at least 6 months after and that's likely a good thing as there are bound to be several dot releases after Monterey goes gold.

You just confirmed that best to wait out the Apple changes until all the rest of the system catches up. I also find it interesting that all the years I have participated in these discussions that I have never seen any report by a user of any security issue on their Mac (assuming they did not update immediately). Maybe just lucky, who knows.

Just because you haven't personally witnessed malware in the wild doesn't mean it does not exist or is not a threat. The macOS Big Sur 11.6 update contains two very bad very high risk zero-day fixes that are certainly being used in the wild to attack macOS and the attacks require zero action on your part. All an attacker has to do is send you a malicious message or email and you will be remotely hacked and they can install malware on your Mac. Apple patched it before most of the cyber criminal underground knew about it. But the cat is out of the bag now and the vulnerabilities are known and various cyber criminal groups are certainly going to start using the zero-day vulnerabilities. The longer you wait to patch the greater the risk of being hacked. There is certainly an increase of macOS malware in the wild, there are even native Apple Silicon (arm64) binaries and Universal binaries (x86_64/arm64) being used with malware.

It is absolutely critical to install the dot releases and security updates for macOS. You can keep your ear to the ground in the tech forums to see if a lot of people experience problems and then wait a bit. But you shouldn't wait longer than a week or two to install critical security updates and dot releases with many bug fixes included. It is extremely rare for Apple to have a problematic update that causes massive trouble requiring it to be pulled from distribution and re-released. It happens and sometimes it takes Apple awhile to fix it. The last one was an update that broke kerberos authentication but that only affected corporate networks using ActiveDirectory. There was a workaround and the Monterey WWDC hit at the same time so there was a delay in Apple releasing a fix. Those impacted were not a large number of Mac users but those with an IT department who could apply the workaround. Again, something like that only happens once every few years or so. It is not a common occurrence.

The only time you should be extra cautious is when there is a major new release such as the upcoming macOS Monterey. Although it's been beta tested for a considerable amount of time there most certainly will be problems on day one. You will certainly need to review your non-AppStore applications are compatible and up-to-date before you install Monterey. You won't need to update to Monterey for security reasons. Apple will patch Big Sur for any new security issues.

When people do not update to the latest dot release version they miss out on many bug fixes. When they ignore security updates they put themselves at considerable risk of being hacked or infected with malware.

Most of the problems people have when installing dot release updates or security updates are the result of some other problem such as a malware infection, old security endpoint software, left over kernel or system extensions or possible hardware failures. Or 3rd party software that hasn't been updated in a long time and is no longer compatible.

I have worked for three international corporations, two name recognition computer hardware/software vendors, and another name recognition system integrator — all in senior UNIX technology consulting/planning/integration roles. One organization had teams of resources in the field that sat down with customer leadership and technical teams, asking and listening to how they used their existing technology. Reports were sent to the employer engineering executives and product managers responsible for the operating system features and release schedule. New, or revised product offerings resulted.

As a fellow user, I cannot speculate about internal Apple business decisions. There appears to be a gap in both quality control, and retained knowledge of how customers use Apple operating systems and layered products, that lead to disappointment when productive features are impacted in future operating system releases.

I'm not arguing what you state and I agree with it all I'm just saying that sometimes I feel I spend as much time fixing the new bugs as I would if I had to erase my drive and reinstall from a clean backup if I got infected by malware. By the way I always update my system within what I consider a reasonable length to time.