nfd2nfc

A macOS tool that watches directories and converts NFD filenames to NFC in real time, ensuring cross-platform compatibility.

What is NFD/NFC?

Unicode has two main ways to represent composed characters such as Korean Hangul, accented Latin (é, ü, ñ), Japanese kana (が, ぱ), and more:

• NFC (Composed): One codepoint per character — 가 = U+AC00
• NFD (Decomposed): Base + combining marks — 가 = U+1100 U+1161

macOS stores filenames in NFD, while Windows and Linux use NFC. This mismatch causes problems when sharing files across platforms:

• Hangul syllables appear as decomposed jamo (e.g., 한글 → ㅎㅏㄴㄱㅡㄹ)
• Accented characters may render or sort incorrectly
• Git sees identical files as untracked or modified
• Cloud sync and archive tools fail to match paths

nfd2nfc provides an interactive TUI and a background watcher service that handles conversion automatically.

Features

• Real-time monitoring — Converts NFD filenames to NFC as soon as they appear
• Flexible watch paths — Mix watch/ignore actions with recursive/children modes to control exactly which directories are monitored
• Manual conversion — Browse the filesystem and convert names between NFD and NFC on the spot
• Log viewer — Review past watcher logs or follow new entries live
• Intuitive controls — Every keybinding is shown on screen, and full mouse support is included

Home

The Home tab displays the current watcher service status and provides controls to start, stop, or restart it.

Config

The Config tab manages which directories the watcher monitors. Each path entry has an action (watch or ignore), mode (recursive or children), and validation status.

Logs

The Logs tab lets you browse past watcher logs and follow new entries in real time. Logs are stored in macOS system logs, and retention is managed by the OS.

Browser

The Browser tab lets you inspect files and directories for their Unicode normalization form and convert them directly. The watcher only picks up newly created or modified files, so use this tab to convert any existing NFD names.

Limitations

nfd2nfc solves the root cause of filenames breaking across operating systems — macOS storing them in NFD. However, other software (browsers, email services, cloud storage, messaging apps, archive tools, etc.) may independently convert filenames to NFD when transferring files. This is application-level behavior outside the scope of nfd2nfc.

Installation

Requires Homebrew.

brew install elgar328/nfd2nfc/nfd2nfc

Then run it:

nfd2nfc

On first launch, the watcher service is automatically registered via brew services. After that, you can start and stop it from the app.

Permissions

If macOS repeatedly prompts for folder access when the watcher converts files, grant Full Disk Access to the watcher binary:

1. Run which nfd2nfc-watcher to find the binary path
2. Open System Settings → Privacy & Security → Full Disk Access
3. Click +, press Cmd+Shift+G, paste the path from step 1, and add it

Note — macOS Tahoe 26.1–26.2 bug: These versions have a known issue where CLI binaries cannot be added to Full Disk Access through System Settings. A fix has been reported in macOS 26.3 beta.

Upgrading from v1

brew upgrade nfd2nfc

v2 replaces the previous CLI with a more user-friendly TUI. The config format (~/.config/nfd2nfc/config.toml) has changed as well, so you will need to re-add your watch paths in the Config tab after upgrading.

Uninstallation

brew uninstall nfd2nfc

License

MIT