MTP File Transfer in Rust on macOS — Why I Wrote My Own Stack

All tests run on an 8-year-old MacBook Air. All results from shipping 7 Mac apps as a solo developer. No sponsored opinion.

HiyokoMTP transfers files between Android and Mac via MTP. The obvious approach — use libmtp — doesn't work well on macOS. So I wrote a custom MTP implementation. Here's why, and what that looks like.

The libmtp problem on macOS

libmtp is the standard C library for MTP. On Linux, it works well. On macOS, it conflicts with IOKit's USB ownership model.

macOS claims USB devices at the system level. libmtp tries to claim them again at the library level. The result: connection failures, device not found errors, crashes. Unreliable enough to be unusable for a shipping product.