The macOS update cycle has become fairly consistent over the last few years, with the final minor release of the cycle taking place in July, a couple of months before the start of the next release cycle. El Capitan and Sierra ran true to form, and there are still plenty of Macs happily running 10.11.6 or 10.12.6, even though neither gets any further security updates.

High Sierra’s cycle was more troubled, and the first attempt at 10.13.6 was delivered on 9 July 2018. Then on 24 July came a Supplemental Update for the latest MacBook Pro models, but on 28 August Apple had to release a second Supplemental Update for those models to fix further problems, just four weeks before shipping Mojave on 24 September.

Although the early part of Mojave’s cycle looked more orderly, it became more complicated in July this year. First there was the Zoom web server vulnerability, which Apple addressed using an unusual if not unique use of its malware removal tool MRT, to remove what had been perfectly legitimate commercial software, then turned out to have serious vulnerabilities. After a succession of MRT updates, Apple released 10.14.6 on 22 July.

In the past, Apple has released the EFI updates needed to start the next cycle with the x.6 update, a strategy which worked successfully in 10.13.6 and spared the initial Mojave release from having to include full firmware updates as well as the major macOS release. That may well have been the strategy again, as 10.14.6 brought with it firmware updates across the board, bringing versions in line with those of Catalina betas.

The 10.14.6 update is quite substantial, with significant changes in basic services like Bluetooth and iCloud support, as well as in bundled apps such as News, Notes, Photos and Safari. But it quickly became apparent that all wasn’t well with its firmware updates: the concomitant security updates were pulled, and some MacBook Pro users complained that putting their Macs to sleep resulted in shutdown, probably the result of a kernel panic.

Apple restored the Sierra and High Sierra Security Updates a week later, on 29 July, then on 1 August released its first Supplemental Update to 10.14.6, which it claimed addressed problems in certain Macs when waking from sleep. This turned out to contain patched firmware updates for just four MacBook Pro models, and a new kernel.

Still the problems continued, and to add to them it became clear that macOS, like iOS, now suffered from a security vulnerability which had been fixed back in May, but had subsequently become unfixed. Although the risk of exploitation in macOS was much lower than in iOS, where it re-enabled an old jailbreak, Apple needed to re-apply the fix which it had inadvertently unfixed.

So on 26 August, Apple released a new version of the 10.14.6 Supplemental Update which included the patched kernel and brought an update to the iBridge firmware used in Macs with T2 chips, the purpose of which was never explained. Its release notes stated that this also fixed an issue which could lead to impaired performance with very large files, and another for problems updating some of Apple’s own apps.

It has taken three large updates over a period of five weeks for Apple to complete the 10.14.6 update, only slightly better than the fiasco that happened with High Sierra a year earlier.

It’s easy to speculate why this has happened for a second year in succession. I’m fairly confident that two major factors have been the other pressures on Apple’s engineers to get Catalina ready for a release date which is determined little by maturity and almost entirely by the calendar. All this is going on when most families are trying to get away on the main holiday of the year, leaving many engineers separated from their families and frazzled by the pressure of multiple deadlines.

For users, system administrators and developers – who have similar exacerbations – it has all been made worse by Apple’s silence on these problems and repeated surprise updates. Many will have only just returned to work, or will be doing so very shortly, to discover the work required to catch up, knowing that in just a few weeks they have Catalina to look forward to.

Not only that, but it now looks as if the first release of Catalina will contain EFI firmware updates for all capable Macs, will rearrange the APFS boot container to create its new read-only system volume, replace pretty well every file in macOS, and render unusable any remaining 32-bit software. As the cliché goes, something of a perfect storm. Maybe Apple misnamed macOS 10.15, and it should have been Hurricane Catarina.