An issue preventing some external drives from mounting onto a Mac running macOS Sonoma has plagued users for months, and it probably was caused by changes Apple made to drive handling.
A LaCie external drive
A LaCie external drive
Hardware support is a common source of problems for operating system updates, and macOS is no exception. Updates to operating systems can cause some types of devices connected to a Mac or MacBook to suddenly stop working, infuriating users in the process.
In some cases, this is a relatively short-lived issue that Apple corrects quickly.
External drive support in macOS Sonoma is partially broken, and it’s probably Apple’s fault
External drive support in macOS Sonoma is partially broken, and it’s probably Apple’s fault