diff --git a/app.js b/app.js
index f1180cf..8685a61 100644
--- a/app.js
+++ b/app.js
@@ -993,8 +993,34 @@ class TeeTracker {
                 // This will automatically fall back to localStorage if Nextcloud has no data
                 await this.loadData();
                 
-                // Save the loaded/merged data to Nextcloud
-                await this.saveData();
+                // Only save to Nextcloud if we actually have data to save
+                // This prevents overwriting existing Nextcloud data with empty arrays
+                if (this.teas.length > 0 || this.entries.length > 0) {
+                    await this.saveData();
+                } else {
+                    // No data to save, but check if Nextcloud has existing data
+                    const existingTeas = await ncStorage.loadFile(DATA_DIRECTORY + 'teas.json');
+                    const existingEntries = await ncStorage.loadFile(DATA_DIRECTORY + 'entries.json');
+                    
+                    // If Nextcloud has data, keep it and load it
+                    if (existingTeas || existingEntries) {
+                        if (existingTeas) {
+                            this.teas = existingTeas.map(tea => ({
+                                ...tea,
+                                organic: tea.organic !== undefined ? tea.organic : false,
+                                rating: tea.rating !== undefined ? tea.rating : 3
+                            }));
+                        }
+                        if (existingEntries) {
+                            this.entries = existingEntries.map(entry => ({
+                                ...entry,
+                                teaspoons: entry.teaspoons !== undefined ? entry.teaspoons : 1
+                            }));
+                        }
+                        // Don't save, just use the existing Nextcloud data
+                    }
+                    // If Nextcloud has no data and we have no data, nothing to do
+                }
                 
                 this.showStatusMessage('✅ Konfiguration gespeichert und Daten synchronisiert!', 'success');
             } else {