By Mike Wuerthele
Thursday, October 24, 2019, 11:52 a.m. EST (2:52 p.m. ET)
If you’re like us, you have a stack of macOS installers of different vintages ready to go at any time. The problem is that the certificates on most of them expire today, rendering them useless.
Certificate expiring on macOS Mojave update 10.14.6 – Photo credit Medium
So here’s what’s going on: Apple has security certificates on installers for macOS. Almost all of these for older versions of operating systems expire at some point on Thursday. It’s not Apple’s root certificate – which would be worse – but the primary and intermediate certificates that expire.
This means that any USB sticks you preloaded and made that are not Catalina will probably not work when you need them. So it’s time to update them.
But maybe not right away. As a post on Way, and confirmed just before this article went online, the macOS Mojave 10.14.6 update program currently available through Apple has the old certificate. Therefore, you can download it now, but it will not work if you do, as it will not be validated as it is after 1:29 p.m. EST – when the package has expired.
The installed operating systems are correct, so there is nothing to worry about. But, if you try to run an installation program, you will receive a warning that the copy of the installation program may be damaged or simply cannot open because the package is no longer approved.
So if you are a system administrator or just want to get ready, there is a little work to do to keep your tools working. You may want to wait until October 24 to do so.
All of this has happened before, and it will happen again. Fortunately, at least for operating systems, you won’t have to do it again until 2029 after getting the new images.