training-academy/docs/archive/DATA_LOSS_INCIDENT.md

🚨 DATA LOSS INCIDENT REPORT

Date: November 12, 2025

Summary

During game mode cleanup (removing obsolete HTML screens), user data was reset to defaults. This includes:

• Linked image/video directories
• Player statistics
• Photo gallery
• Custom tasks
• Personal preferences

Root Cause

When game screen elements were removed from index.html, the application's initialization sequence likely encountered errors looking for expected DOM elements, causing the DataManager to reset localStorage to default values.

Impact

• All user-configured data lost
• User must manually re-add linked directories
• Custom content must be re-imported
• Player progress reset to zero

Prevention Measures

1. Add data backup system before major changes
2. Implement graceful error handling for missing DOM elements
3. Add data export/import functionality
4. Create pre-change data validation

Recovery Actions

1. User needs to re-link media directories
2. Re-import custom images and tasks
3. Reconfigure preferences
4. Source files should still exist in original locations

Lessons Learned

• Always backup localStorage before structural changes
• Test initialization sequence after DOM modifications
• Implement more robust error handling in DataManager
• Consider separating user data from application state

Status

• ❌ Data recovery: Not possible
• ⚠️ User impact: High (requires manual restoration)
• ✅ Application stability: Confirmed working
• 📋 Action items: Implement backup system