Copying login keychains between Macs fails on Secure Enclave Macs with Tahoe

A recent technical discovery highlights a significant change in macOS Tahoe regarding the manual migration of login keychain files. Historically, administrators could move keychain files between Mac devices to maintain user credentials. However, on Macs equipped with Apple's Secure Enclave, this process is no longer viable. The Secure Enclave binds keychain encryption keys directly to the specific hardware of the original device, preventing the successful decryption of these files when moved to a new system. This shift underscores Apple's ongoing commitment to hardware-backed security, which prioritizes data integrity and protection against unauthorized access. For IT professionals and system administrators, this means that traditional manual migration methods are obsolete for newer hardware configurations. Moving forward, organizations must rely on official Apple-supported methods, such as MDM-based configuration profiles or iCloud Keychain synchronization, to manage user credentials across fleets of devices effectively.