Legacy system extension warning on Mac
I received the following message. Can someone tell me what it's all about?
[Re-Titled by Moderator]
MacBook Pro 13″, macOS 15.1
Question marked as
In the past, third parties who wanted to provide device drivers and the like would provide them in the form of kernel extensions. A kernel extension runs at operating system level – with potentially full control of the machine, same as the operating system itself has.
System extensions run in user space, and the operating system can restrict their privileges. This is, theoretically, a more secure design. The idea of running system services in user space has been around for a while. Like NeXTstep (on which it is partially based), macOS uses a variant of Carnegie Mellon's Mach microkernel. I believe that one goal of Mach was to be able to run system services in user space.
Unfortunately, there is a performance cost to doing things that way. So for a very long time, macOS has run things in system space. Now that processors are much faster than they once were, Apple has started to deprecate – and, in some cases, to drop all support for – various kernel extension interfaces.
Deprecated Kernel Extensions and System Extension Alternatives - Support - Apple Developer
It sounds to me like the messages are saying that your Canon printer and scanner (?) drivers may not run on future versions of macOS. The idea is to prompt Canon to rewrite their drivers using new interfaces before that happens.
A similar thing happened with the 32-bit to 64-bit transition, where High Sierra and Mojave put up warnings about 32-bit applications, but continued to run them … just before Catalina broke those applications completely.
