Mt. Sync

Mount or sync network storage anywhere

A C++ GTK4/libadwaita frontend to rclone. Configure backends, browse remote file systems, and manage sync/copy/move/mount jobs with live progress — all from a native GNOME desktop application backed by a persistent daemon.

Features

• Backend configuration — Create, edit, and delete rclone remotes via dynamically generated forms derived from rclone's own provider option metadata; each remote row shows a type-appropriate provider icon (Google Drive, Dropbox, Backblaze B2, MEGA, Box, Google Cloud Storage, Proton Drive, and more) with automatic light/dark variants; unknown providers fall back to symbolic icons; each remote also displays its used/free capacity (total, used, free) queried asynchronously via the rclone RC operations/about endpoint
• Dual-pane file browser — Two independent browser panes with column view, breadcrumb navigation, back history, MIME-type icons, sortable columns, and a status bar showing file/folder counts and total size; hidden files toggled per-pane; compact navigation bar with provider icon in the remote dropdown; swap button physically exchanges remote and path between panes; Compare button runs rclone check between the two panes and displays results in a paginated 7-column dialog grouped by subdirectory — filename, size, and modified date shown only on the side where the file exists; status glyphs → (source only) ← (dest only) ≠ (differs) = (identical); all seven columns support interactive sorting and files stay grouped with their directory header when any column sort is active; five filter toggles (← → = ≠ !) in the action bar show rows by status (all on by default; deactivate to hide that category) — directory headers with no visible children are suppressed automatically
• Jobs system — Define Sync, Copy, Move, and Mount jobs; run them on demand or on a cron schedule; real-time progress with transfer stats (files, speed, ETA); jobs persist across GUI restarts; each job row shows a type icon, a SourceDir → DestDir display name, and a footer with the job UUID and last status; the add/edit dialog is split into three tabs — Job (type, source, destination, filters, dry run, bi-directional sync, checksum, mount options), Schedule (enable toggle; preset dropdown — Every minute, Hourly, Daily, Weekly, Monthly, Custom; text entries for Minute, Hour, and Day of Month each with a clear-to-* button; Day of Week checkbox row Sun–Sat; Month checkbox grid Jan–Dec; live preview panel showing the raw cron expression, a human-readable description, a calendar with run days marked for the current month, and a scrollable list of the next 15 upcoming execution times), and Advanced (bandwidth limit, parallel transfers, retries on failure, extra rclone flags appended to the RC call at run time — supports --flag value, --flag=value, and boolean --flag forms); Sync jobs support bi-directional sync mode (rclone bisync), copy empty directories, and file include-pattern filters; Mount jobs show active state and can be stopped/unmounted; checksum verification disabled by default; Save button to store job without running; scheduled jobs skip execution if the previous instance is still running; failed jobs are automatically retried up to a configurable count with exponential backoff (2 s, 4 s, 8 s, … capped at 60 s) before being marked as failed; activity log panel shows the last 100 entries in a structured column view (Time, State, Job ID, Type, Contents) with colour-coded state labels, newest first
• Background daemon — mtsync --daemon keeps jobs running when the GUI is closed; GUI reconnects automatically on next launch; daemon starts rclone RC on startup; periodic mount liveness checks detect and mark stale FUSE mounts; HTTP request timeouts and poll-rate guards prevent resource exhaustion during network outages
• System tray icon — StatusNotifierItem tray icon with Open/Quit menu; Open re-launches the GUI if it is not running; animated spinner shown while any job is active; custom Mt. Sync-branded idle icon rendered via Cairo and bundled as a GLib resource
• Desktop notifications — Optional notifications via notify-send or kdialog; independently configurable for job start, successful completion, and completion with errors/warnings
• Settings — Startup & shutdown behaviour (autostart, tray), notification toggles, transfer defaults (bandwidth limit, checksums, parallel transfers, retries on failure), rclone binary path override, global rclone flags applied to every job at execution time (lowest priority — per-job extra flags and explicit job settings take precedence); persisted to ~/.config/mtsync/settings.json

Dependencies

Requires rclone, a C++23 compiler, CMake 3.25+, and the following libraries:

sudo apt install \
  libgtkmm-4.0-dev \
  libadwaita-1-dev \
  libsoup-3.0-dev \
  nlohmann-json3-dev

Building

Create the build directory, then configure and build:

mkdir build
cmake \
  -DCMAKE_BUILD_TYPE:STRING=Debug \
  -DCMAKE_EXPORT_COMPILE_COMMANDS:BOOL=TRUE \
  -DCMAKE_C_COMPILER:FILEPATH=/usr/bin/clang \
  -DCMAKE_CXX_COMPILER:FILEPATH=/usr/bin/clang++ \
  --no-warn-unused-cli \
  -S . -B build -G "Unix Makefiles"
cmake --build build

CMAKE_EXPORT_COMPILE_COMMANDS writes a compile_commands.json into the build directory, which IDEs and tools such as clangd use for accurate code intelligence. Use Debug for development; substitute Release for an optimised binary.

Installing

Pre-built packages are produced by CI for each push to the build branch. Package filenames follow the name_version_distro_arch.ext convention (e.g. mtsync_0.8.1_ubuntu24.04_x86_64.deb).

DEB (Ubuntu)

sudo apt install ./mtsync_*_ubuntu*_x86_64.deb

Packages are built for Ubuntu 24.04, 25.10, and 26.04. Install the one that matches your release.

RPM (Fedora)

sudo dnf install ./mtsync_*_fedora*_x86_64.rpm

AppImage

chmod +x mtsync_*_x86_64.AppImage
./mtsync_*_x86_64.AppImage

No installation required — the AppImage is self-contained and runs directly.

From source

cmake --install build --prefix ~/.local
gtk-update-icon-cache ~/.local/share/icons/hicolor
update-desktop-database ~/.local/share/applications

Installing places the binary in ~/.local/bin, registers the application icon (256×256 PNG and scalable SVG) with the hicolor theme, and installs the .desktop file so the icon appears in the launcher and taskbar.

Flatpak

Build and install the Flatpak bundle from the packaging manifest:

sudo apt install flatpak flatpak-builder
flatpak install --user flathub org.gnome.Platform//48 org.gnome.Sdk//48
flatpak-builder --user --install --force-clean build-flatpak packaging/com.mtsync.MtSync.yml

Launch with flatpak run com.mtsync.MtSync. rclone is bundled inside the Flatpak — no host installation needed. The manifest grants --filesystem=home, so enabling Start daemon on login in Settings writes the autostart entry directly to the host's ~/.config/autostart/ with the correct flatpak run --command=mtsync com.mtsync.MtSync --daemon exec line.

Snap

Build and sideload the .snap:

sudo apt install snapcraft
snapcraft pack
sudo snap install --dangerous mtsync_*.snap

The Snap uses strict confinement. To enable Start daemon on login, connect the privileged personal-files plug once (sideloaded snaps do not auto-connect it):

sudo snap connect mtsync:dot-config-autostart :personal-files

Without that connection the autostart toggle fails silently, because the home plug cannot write to hidden directories such as ~/.config/autostart/. rclone is bundled inside the snap. The Local remote in the Browse tab is resolved via $SNAP_REAL_HOME so your real home directory is listed rather than the empty snap-private data directory.

Running

./build/mtsync          # launch GUI (starts daemon automatically)
./build/mtsync --daemon # run as background daemon only

Mt. Sync expects rclone to be available on PATH.

Architecture

MtSyncApplication (Gtk::Application)
 └── MtSyncWindow (Gtk::ApplicationWindow)
      ├── AdwHeaderBar + AdwViewSwitcher
      └── AdwViewStack
           ├── BrowserView   — dual-pane file browser (two BrowserPane widgets)
           ├── JobView       — job list with progress, run/stop controls, activity log
           ├── BackendsView  — remote list with provider icons and drill-down edit form
           ├── SettingsView  — application and transfer settings
           └── AboutView     — version, license, and copyright

MtSyncDaemon (background process, mtsync --daemon)
 ├── IpcServer             — Unix socket at ~/.cache/mtsync/socket
 ├── TrayIcon              — StatusNotifierItem + dbusmenu via D-Bus
 └── RcloneManager
      ├── RcloneCli         — Gio::Subprocess for one-shot commands
      └── RcloneRc          — libsoup HTTP to rclone RC daemon

GUI ↔ Daemon communication: The GUI connects to the daemon via a Unix socket IPC. The GUI starts the daemon automatically if it is not already running. Jobs continue executing in the daemon when the GUI window is closed.

D-Bus services: com.mtsync.Daemon (daemon) exposes ShowWindow and Quit methods.

libadwaita is used via its C API bridged to gtkmm with Glib::wrap(), as no C++ bindings (libadwaitamm) are available.

All async I/O dispatches on the GLib main loop — no manual threading.

Configuration

Path	Purpose
~/.config/rclone/rclone.conf	rclone backend configuration
~/.config/mtsync/jobs.json	Mt. Sync job definitions
~/.config/mtsync/settings.json	Mt. Sync application settings
~/.cache/mtsync/socket	IPC socket (daemon ↔ GUI)

License

GNU General Public License v2.0. See LICENSE for details.