What does a Lightroom catalog contain, and what happens when it corrupts?
Short answer: A Lightroom Classic catalog (.lrcat) is a SQLite database (a lightweight, file-based database format) containing every adjustment, metadata tag, collection membership, star rating, and develop preset you have applied to every photo. The photos themselves stay wherever you stored them. Corruption happens when a write to the SQLite database is interrupted mid-transaction — most often during a power cut, a forced shutdown, or when the drive holding the catalog runs out of space. The result is that Lightroom opens but cannot read the catalog, showing errors like "the catalog could not be opened" or "an unexpected error occurred".
Step-by-step Lightroom catalog recovery
Step 1: Use Lightroom's built-in catalog repair
Before anything else, try Lightroom's own repair tool. On Windows, hold the Alt key while double-clicking the Lightroom shortcut. On macOS, hold Option while launching from Applications. A dialog appears offering to check and repair the catalog. Choose Test Integrity first, which scans the SQLite database for errors. If errors are found, choose Repair Catalog. Lightroom will create a repaired copy. This tool succeeds in roughly 60% of software-level corruption cases.
Step 2: Restore from a catalog backup
If the built-in repair fails, locate your catalog backups. The default location on macOS is Pictures/Lightroom/Backups/; on Windows it is Documents\Adobe\Lightroom\Catalog Backups\. Each backup is a timestamped folder containing a compressed .lrcat file. Extract the most recent backup, copy it to your catalog folder, rename it to match your existing catalog name, and launch Lightroom pointing to it. You will lose edits made after the backup date, but everything before that date will be intact. This is why Lightroom's setting to back up daily (rather than weekly) matters so much.
Step 3: Manual SQLite repair for advanced users
If you have no backup and the built-in repair tool fails, the underlying SQLite database can sometimes be partially repaired using the sqlite3 command-line tool. The command sqlite3 corrupted.lrcat ".recover" | sqlite3 repaired.lrcat attempts to extract all readable rows from the damaged database into a new file. This is a technical process, but it can recover partial data — typically all edits up to the point of corruption, with the most recent session's changes potentially missing.
Step 4: The India angle — catalog corruption from laptop overheating
We see a specific India-pattern catalog corruption: the laptop overheats during a long Lightroom export session (Indian summer temperatures plus dust-clogged fans), the system performs a thermal shutdown, and the Lightroom catalog write operation is interrupted mid-transaction. This corrupts the SQLite database. The fix starts with cleaning the laptop's cooling system (thermal paste replacement and fan cleaning, ₹600–₹1,500 at our workshop) to prevent recurrence, followed by catalog recovery as above. Our data recovery team handles both the hardware and the catalog-level work in one visit.
When to call a recovery service (and what it costs in India)
When DIY ends
Stop and call a professional if: the drive holding the catalog shows errors in Disk Utility, sqlite3 returns "disk I/O error" rather than data corruption errors (indicating hardware failure not software), the laptop crashes repeatedly during the recovery attempt, or the SQLite .recover command produces an empty or very small output file.
Typical cost in India
Software-level SQLite catalog repair (healthy drive): ₹2,000–₹4,000. Physical drive recovery if storage has failed: ₹5,000–₹18,000. Lightroom repair combined with laptop thermal service: ₹3,000–₹6,000 total. Also see the Final Cut Pro library recovery guide for a comparable creative-workflow recovery scenario.
A note from the LRW Engineer Team
Enable two Lightroom settings before a problem happens: set catalog backup frequency to "every day" (Catalog Settings → General → Back Up Catalog), and enable "Automatically write changes into XMP" (Catalog Settings → Metadata). The second setting writes your develop adjustments into XMP sidecar files alongside RAW images, meaning your edits are protected even if the catalog is completely destroyed. Both settings are off by default; turning them on takes 30 seconds.