Apple’s dropping AFP support in macOS 27, and it’s about time. The Apple Filing Protocol was innovative in the 1980s, but it’s been obsolete for years. Here’s why SMB won and what we can learn from Apple’s walled garden approach to network storage.

This is a continuation of my earlier post about Time Capsule deprecation, but focused on the technical reasons why AFP couldn’t compete with industry standards.

What AFP Actually Was

AFP was Apple’s proprietary network file system protocol. Introduced in 1985, it was designed for AppleTalk networks where Macs talked to each other and shared files seamlessly. The idea was elegant - plug in a Mac, and it would automatically discover and connect to other Macs on the network.

AFP handled authentication, file sharing, and printer sharing in one protocol. It was ahead of its time in some ways. The automatic service discovery meant you didn’t need to configure IP addresses or mount points. Macs just found each other.

The protocol was optimized for Apple’s ecosystem. It understood Mac file metadata, resource forks, and the Finder’s view of the file system. When you shared a folder via AFP, it preserved all the Mac-specific attributes that other protocols would strip away.

But AFP only worked with Apple devices. That was the fundamental limitation. While third-party implementations like Netatalk allowed Linux/Unix and NAS devices to run AFP servers, and some commercial solutions offered AFP server support for Windows, its primary use and full compatibility were always with the Mac platform. You couldn’t reliably share files with Windows computers or most NAS devices using AFP.

How SMB Became the Standard

SMB started as IBM’s LAN Manager protocol. Microsoft licensed it and built it into Windows, but the real breakthrough came when Samba reverse-engineered the protocol for Linux. Suddenly, you had cross-platform file sharing that actually worked.

SMB evolved through multiple versions. SMBv1 was insecure and slow. SMBv2 fixed the performance issues. SMBv3 added encryption and better security. Each version addressed real problems that users encountered in production environments.

The industry standardized on SMB because it worked everywhere. Windows servers, Linux servers, NAS devices, network printers - they all spoke SMB. You could mix and match hardware from different vendors and still share files reliably.

SMB became the protocol of enterprise environments. When businesses needed file sharing that worked across different operating systems, SMB was the only choice. Apple’s AFP was never an option in mixed environments.

Why AFP Became Obsolete

Apple made the shift away from AFP much earlier. SMB became the primary file sharing protocol in OS X 10.9 Mavericks (2013). The ability to run an AFP server was removed in macOS 11 Big Sur (2020). macOS 27 is expected to remove the AFP client entirely, but its obsolescence began years ago.

AFP evolved significantly through version 3.x. While SMB went through major revisions to address security, performance, and compatibility issues, AFP 3.x introduced major changes like support for Unicode filenames, UNIX-style POSIX permissions, larger file sizes (4GB+), and the shift to TCP/IP-only transport. However, its evolution stalled after 3.x, allowing SMB to overtake it with continued improvements.

The Mac market share made AFP irrelevant. When Macs were a tiny fraction of computers in business environments, AFP couldn’t compete with protocols that worked across platforms. Apple’s walled garden approach worked for consumers but failed in enterprise.

SMB’s performance advantages became apparent over time. Historically, AFP often outperformed early SMB versions (SMB1 and early SMB2 implementations on Macs). The switch to SMB in OS X 10.9 was initially plagued with performance issues. It’s only with the maturity of SMB3 in recent macOS versions that SMB’s performance definitively matches or surpasses AFP for most tasks, offering features like multichannel that AFP couldn’t provide.

Security became a major concern. AFP 3.x did support Kerberos authentication when connecting to macOS/OS X Server and Active Directory environments, and it also supported ACLs. The issue wasn’t that AFP couldn’t provide these features, but that its implementation was proprietary and less universally adopted or maintained compared to SMB’s industry-standard approach. Enterprise environments needed security features that worked consistently across all platforms.

Apple’s own products moved away from AFP. Time Capsule was one of the last devices to use AFP exclusively. Apple’s servers, network storage, and even file sharing features in macOS gradually shifted to SMB. AFP became a legacy protocol that Apple maintained for backward compatibility.

The Technical Differences That Mattered

SMB uses TCP/IP as its transport layer. AFP was designed for AppleTalk, but later versions (AFP 2.2+) adapted to run over TCP/IP, and AFP 3.0+ relied exclusively on TCP/IP (port 548). While it started on AppleTalk, later versions were built on IP for communication.

SMB handles network interruptions better. Modern SMB implementations can reconnect automatically when network connections drop. AFP was more fragile - if the connection broke, you often had to manually reconnect.

SMB’s file locking is more sophisticated. When multiple users access the same file, SMB handles conflicts better than AFP. This matters in business environments where file sharing is common.

SMB supports more file system features. Extended attributes, symbolic links, and other advanced file system features work better with SMB than AFP. AFP was designed for simpler file systems.

SMB’s error handling is more robust. When things go wrong, SMB provides better error messages and recovery options. AFP’s error handling was often cryptic and unhelpful.

What Apple Learned

Walled gardens don’t work for network protocols. AFP was elegant within Apple’s ecosystem, but it couldn’t compete with open standards that worked across platforms. Apple learned this lesson and moved to industry standards.

Proprietary protocols become maintenance burdens. Apple had to keep AFP working, secure, and compatible with new macOS features. That’s expensive engineering effort for a protocol that only works with Apple devices.

Industry standards win through adoption. SMB became the standard not because it was technically superior to AFP, but because it worked everywhere. The network effect of compatibility outweighed any technical advantages AFP might have had.

Apple’s strength is integration, not protocols. Apple excels at making complex technologies simple to use. AFP was Apple trying to reinvent network file sharing instead of making existing standards work better.

The Legacy of AFP

AFP wasn’t a failure - it was ahead of its time. The automatic service discovery and seamless integration that AFP provided were innovative. Modern protocols like mDNS and Bonjour borrowed some of these ideas.

Apple’s walled garden approach had limits. AFP worked great for Mac-only environments, but it couldn’t scale beyond Apple’s ecosystem. The lesson is that network protocols need broad compatibility to succeed.

The transition to SMB was inevitable. Apple’s move away from AFP wasn’t a defeat - it was recognition that industry standards provide better long-term value than proprietary protocols.

Time Capsule users are the last holdouts. Most Mac users moved away from AFP years ago. Time Capsule was one of the few devices that still relied on it exclusively, but Apple officially discontinued the AirPort Time Capsule hardware in 2018. The “last holdouts” are using unsupported, legacy hardware. Time Machine over SMB has been the modern standard for network backups to current NAS devices for years.

What This Means for Network Storage

SMB is the only choice for cross-platform file sharing. If you need storage that works with Macs, Windows, Linux, and mobile devices, SMB is your only option. AFP was never going to be that protocol.

Modern NAS devices are built around SMB. Synology, QNAP, and other NAS manufacturers optimize their SMB implementations for performance and compatibility. They don’t waste engineering effort on protocols that only work with one vendor’s devices.

Apple’s focus shifted to making SMB work better. Instead of maintaining AFP, Apple improved SMB support in macOS. The result is better compatibility with industry-standard storage without sacrificing the user experience.

The future is SMB and cloud storage. Local network storage uses SMB. Remote storage uses cloud protocols. AFP doesn’t fit into either category, which is why it’s finally being retired.

AFP served Apple well for decades, but it’s time to let it go. The industry moved on, and Apple is finally catching up. SMB provides everything AFP did and more, with the added benefit of working with the rest of the world.