Announcing macFUSE 5.3.0 - macFUSE

Announcing macFUSE 5.3.0 Posted on 08 Jun 2026

Download macFUSE 5.3.0 macOS 12 or later Apple Silicon or Intel SHA-256: 434a247217a1b070279730a486eaaebebdc01070b66b7f64e26e3cd0f5079d89

Release Notes

General

Update build process to use Xcode 26.5 (macOS 26.5 SDK)
Introduce a new channel API for exchanging FUSE messages with FUSE backends. The new API significantly improves I/O performance for volumes mounted using the FSKit backend.

`FSModule` (`FSKit` Backend)

Add support for the new channel API provided by MFMount.framework
Add support for the new FUSE_INIT flags FUSE_DARWIN_REPLY_BUF and FUSE_DARWIN_PAYLOAD_BUF. The flags allow for zero-copy reads and writes.
Substantially improve I/O performance. Tests with the LoopbackFS reference file system show that reading files is up to 15 times faster than in previous releases.
Improve stability by addressing a race condition when accessing cached volume statistics that could cause the file system extension to crash.

`MFMount.framework`

Introduce a new channel API for exchanging FUSE messages with the FSKit Backend and the Kernel Backend.

MFMount.framework is intended for developers porting FUSE user-space libraries to macOS, or adapting existing libraries to support mounting volumes using the FSKit backend. The framework handles the mount operation and provides a C API for communicating with the backend.

The new channel API exposes FUSE messages as borrowed buffers instead of requiring callers to copy each message into a single contiguous buffer. This allows for zero-copy reads and writes for large payloads when using the FSKit backend.
- Add MFChannelRef for message-oriented communication with a backend. A channel is associated with a volume when the volume is mounted.
- Add MFMessageRef for inspecting received FUSE messages
- Add support for transport-provided reply buffers, allowing read replies to be written directly into the destination buffer
- Add blocking, non-blocking, and polling-style receive APIs
Please note that parts of the MFMount.framework API may still change in future releases.

`libfuse`

Add support for the new channel API provided by MFMount.framework

`libfuse3`

Add support for the new channel API provided by MFMount.framework

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