Why Lightroom Classic is hard to back up
The catalogue is a SQLite database in a single .lrcat file, and while Lightroom is open it holds a write lock and maintains a .lrcat-journal alongside it. Back up the .lrcat mid-transaction and you get a torn file that will not open, or worse, opens and corrupts on first write. Meanwhile the Previews.lrdata and Smart Previews.lrdata bundles grow into tens of gigabytes of JPEG thumbnails that Lightroom will happily regenerate from the originals. And then there are the XMP sidecars sitting next to each RAW — small, important, and often missed by backup tools that filter by extension.
How macup handles it
macup detects the .lrcat-journal file. When it’s present, the agent waits for the session to close or for the journal to clear before snapshotting the catalogue. No torn SQLite files, no ransomware-grade “success” that silently fails on restore. If you keep Lightroom open all day, macup captures the RAW files and XMP sidecars continuously and snapshots the catalogue during the first quiet window.
XMP sidecars are included by default — they carry the edits Lightroom wrote out for round-tripping with Bridge or Photoshop. The preview bundles are excluded by default because Lightroom rebuilds them on demand and they would otherwise dominate your backup set.
Every snapshot is chunked and deduplicated against earlier versions, so a catalogue that grows by a hundred megabytes a day contributes far less than a hundred megabytes to your destination. All data is AES-256 encrypted on the Mac before upload, and your passphrase never leaves the machine.
Recommended policy
A backup set configured like this covers the important things and skips the regeneratable ones:
name: Lightroom Classic
include:
- ~/Pictures/Lightroom
- ~/Pictures/Lightroom/*.lrcat
- ~/Pictures/Lightroom/**/*.xmp
- ~/Pictures/Photos
exclude:
- "**/Previews.lrdata/**"
- "**/Smart Previews.lrdata/**"
- "**/*.lrcat-journal"
- "**/*.lrcat.lock"
- "**/Helper.lrdata/**"
schedule:
mode: continuous
catalogueQuiesce: true
quietHours: 01:00-05:00
destination: macup-cloud
retention:
daily: 30
weekly: 52
monthly: 60Tune further in the macup dashboard per destination.
What you get back
Scrub back to the version of the catalogue from last Tuesday, restore it alongside the current one, and recover the edit stack on a photo that got flattened during a careless develop-preset swap. Or pull a single XMP sidecar out of the history to restore the crop and white balance on one RAW without touching the rest of the catalogue.