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LrCatalogSync

• LrCatalogSync synchronizes the Adobe Lightroom Classic catalog and its helper files to a Samba server.
• It detects when a sync or Lightroom Classic is running on another computer, and prevents opening the Lightroom Classic catalog locally as well as its own sync process in order to keep the data consistent.
• LrCatalogSync starts automatically with Windows and can be found as an icon in the system tray.

How it works

Copied files

The following Lightroom files and folders are synchronized:

• *.lrcat – the main catalog file (SQL)
• *.lrcat-data/ – catalog database (masks, AI selections)
• * Sync.lrdata/ – for Adobe Creative Cloud
• * Smart Previews.lrdata/ – small preview files of Raw/DNG
• * Helper.lrdata/ – helper data for catalog functions

Optional (see settings):

• * Previews.lrdata/ – standard and 1:1 previews (option Sync *Previews.lrdata?)

Backup folder (option Sync backup folder?):

• The Lightroom backup folder (catalog backups) is synchronized separately and in both directions (rclone bisync).

Lock files (Lightroom detection)

The program detects automatically when Lightroom is open and skips the sync:

• *.lrcat.lock – main lock file
• *.lrcat-shm – shared memory segment
• *.lrcat-wal – write-ahead log

Lightroom Classic creates these files when the catalog is opened and deletes them when it is closed.

Requirements

• Windows 10 or Windows Server 2016 or newer
• Internet connection on first start if rclone is not yet available

Installation

1. Download LrCatalogSync from GitHub and start LrCatalogSync.exe – the icon appears in the tray.
2. If no rclone version is available yet, LrCatalogSync automatically downloads the current stable Windows AMD64 release from rclone.org on startup and stores rclone.exe in data/rclone/.
3. On later starts it checks for a newer version. If rclone is already present, it stays usable when the download site cannot be reached.

If the automatic download is not available, download rclone manually from rclone.org, unpack it and enter the folder containing rclone.exe in the settings. A manually configured path is kept and is not replaced automatically.

Usage

Start: double-click LrCatalogSync.exe (can be enabled at system start).

Stop: right-click the tray icon → Exit.

Configuration (GUI)

Right-click the tray icon → Settings

Field	Description
Start automatically with Windows	Run the program automatically at Windows startup
Rclone folder	Folder containing rclone.exe; default is data/rclone/. Another folder can be entered manually.
Log level	DEBUG, INFO, NOTICE, ERROR
Language	System (Windows display language), English or Deutsch. Unsupported Windows languages use English.
Check interval	Check interval in seconds (1 to 999, default 10)
Sync *Previews.lrdata?	Whether the * Previews.lrdata folder (standard and 1:1 previews) is synchronized as well
Local catalog file	Path to the local .lrcat file
Remote catalog path	Target path on the SMB server (e.g. //192.168.1.1/Lightroom/ -> /Lightroom/)
Keep last catalog?	Before syncing, stores a copy of the previous catalog in an extra folder (on the server for uploads, locally for downloads)
Folder name	Name of the folder for this copy
Sync backup folder?	Optional, synchronizes the Lightroom backup folder locally and remotely
Local backup path	Local path where Lightroom stores its backups
Remote backup path	Target path on the SMB server for the backups
Server IP/name	IP or host name of the SMB server
Username / Password	Credentials (stored encrypted)

Settings are stored in data/config/. The user interface and the log messages generated by LrCatalogSync follow the selected language. System uses German or English according to the Windows display language; other languages fall back to English. rclone's own log messages stay in the language provided by rclone.

Tray icon

Tray icon status:

• 🟢 --> ready, no sync active
• 🟠 --> synchronizing the Lightroom backup folder
• 🟡 --> synchronizing the Lightroom catalog
• 🔵 --> Lightroom Classic is active locally and the sync is blocked
• 🔵 --> the PC was restarted during a sync, this recovery process is started
• 🟣 --> a sync is currently running from another computer
• 🟣 --> Lightroom Classic was started on another computer
• 🔴 --> error (e.g. no Samba connection, rclone missing, stale remote lock), see log (set to Debug if necessary)
• ⚪ --> configuration file missing
• --> sync is switched off (tray menu Turn off or USB export open)

Tray menu: USB export, Turn off/Turn on, Settings, Exit.

Logs are located in data/logs/.

USB export (additional tool)

The USB export copies arbitrary folders (e.g. photo library, Lightroom catalog, image archive) to an external drive. The tool is part of LrCatalogSync and also uses rclone.

Opening

Right-click the tray icon → USB export. While the window is open, the normal sync is paused (the menu entry shows "USB export open"). After closing, the previous state (sync on/off) is restored. If a normal sync cycle is running, all inputs and actions are locked until it has finished; the window cannot be closed in that case.

Areas and controls

Area / element	Description
Target	Target folder on the external drive (Browse / Remove). The drive is derived from the path.
Drive	Drive, file system, total size, used (red) and free (green) space; updated automatically
Clear target folder	Empties the target folder after a confirmation. For a drive root, the whole drive is emptied (Windows system folders are kept).
Transfer metadata	Additionally transfers file metadata. Only selectable if the target is NTFS-formatted.
Use hash comparison and verify	Compares files by checksum instead of size/date and automatically runs a checksum comparison after the transfer
Data sources	List of folders to copy (Add / Remove)
Exclude	Custom exclude patterns separated by ; (e.g. *.tmp;*.partial;*Previews.lrdata)
Status log	Messages of the running action (errors in red, successful verification in green)
Progress display	Percentage, current section (e.g. 1/2), speed and elapsed time
Copy to external	Starts the transfer of all data sources into the target folder
Checksum compare	Compares sources and target by checksum without copying anything
Cancel	Cancels the running action
Exit	Closes the window (not possible during an action; closing via the window asks whether to cancel)

Transfer procedure

1. Select the target folder on the external drive.
2. Add one or more data sources. Optionally set exclude patterns, metadata and hash comparison.
3. Click Copy to external.
4. Beforehand it is checked whether the drive and sources are reachable and whether the sources contain Lightroom lock files (*.lrcat.lock, *.lrcat-shm, *.lrcat-wal). If Lightroom is still open, the transfer is rejected and the lock files are listed in the log.
5. Each data source is transferred into its own subfolder of the target folder (name of the source folder). For identical names, the folder name is extended by parent folders or the drive letter and, if necessary, a number.
6. With hash comparison enabled, a checksum comparison follows automatically. The result (missing, differing or unreadable files) is shown in the status log.

Warning: The transfer is a synchronization (rclone sync). Files in the target subfolder that no longer exist in the source are deleted. The source is never modified.

Automatically excluded

Regardless of custom patterns, the following are never transferred or deleted:

• *.lrcat.lock, *.lrcat-shm, *.lrcat-wal, *.lock, Thumbs.db
• Windows system folders in the drive root: System Volume Information, $RECYCLE.BIN, Recovery

Notes

• If the drive is full, the transfer is aborted and the missing space (in GB) is reported in the log.
• Settings (target, sources, excludes, options) are saved automatically in data/config/USBExport.conf. A separate rclone configuration is stored in data/config/USBExportRclone.conf.
• The log is written to data/logs/USBExport.log.
• An existing rclone.exe is required (see Installation).

Troubleshooting (short)

• rclone.exe not found: check the internet connection on first start. With a manual path, the selected folder must contain rclone.exe.
• Samba connection failed: check IP, user, password and network.

Resources

• GitHub: https://github.com/Raychan87/LrCatalogSync
• rclone: https://rclone.org
• Lightroom Classic: https://www.adobe.com/products/photoshop-lightroom-classic.html

Version 1.0.0 – as of: October 2026