Enlarge (credit: Apple)

Earlier this week, various macOS sysadmins began reporting that some Apple devices were failing to upgrade to Big Sur version 11.1. Affected users may briefly see the 11.1 upgrade, but then it disappears from the update UI and from the command line softwareupdate tool despite not having been installed.

Erroneous update request

Developer Victor Vrantchan, of the open source MicroMDM project, says he's found the problem. Some Macs are erroneously requesting 11.0.1 instead of 11.1 from Apple's update server—which update is then rejected if the machine in question is already running 11.0.1 or newer, as most such are.

Apple's update servers don't like it when you ask for a system update that's older than your currently installed version. (credit: Victor Vrantchan )

While the erroneous requests themselves are clear enough, the breaking condition is less so. According to Vrantchan, making the erroneous request "somehow corrupts the state of the software update process," resulting in a system that no longer presents the update as an option in System Preferences at all.

• 

  The 2020, M1-equipped Mac mini. [credit: Samuel Axon ]

Apple is crazy, right? The Mac just had its best year of sales ever, and Cupertino is hitting the platform with a shock like it hasn’t had in nearly 15 years—back in a time when the Mac was not having such a good year. Apple is beginning the process of replacing industry-standard Intel chips with its own, custom-designed silicon.

In a way, we're not just reviewing the new Mac mini—a Mac mini is always a Mac mini, right? We're reviewing an ARM-based Mac for the first time. And this is not exactly the same story as all the other ARM machines we've looked at before, like Windows 10 on ARM—a respectable option with some serious tradeoffs.

Sure, longer battery life and quick waking from sleep are already out there on other ARM computers. But as you may have seen in our hands-on earlier this week , what we're encountering here is also a performance leap—and as you'll also see in this review, a remarkable success at making this new architecture compatible with a large library of what could now, suddenly, be called legacy Mac software.

Enlarge / A promotional image for macOS Big Sur.

Mac users today began experiencing unexpected issues that included apps taking minutes to launch, stuttering and non-responsiveness throughout macOS, and other problems. The issues seemed to begin close to the time when Apple began rolling out the new version of macOS, Big Sur—but it affected users of other versions of macOS, like Catalina and Mojave.

It didn't take long for some users to note that trustd —a macOS process responsible for checking with Apple's servers to confirm that an app is notarized—was attempting to contact a host named oscp.apple.com but failing repeatedly. This resulted in systemwide slowdowns as apps attempted to launch, among other things.

Users who opened Console and filtered to find the error encountered numerous successive errors related to trustd , as pictured below.