diff --git a/cmd/msgvault/cmd/sync.go b/cmd/msgvault/cmd/sync.go
index cc65cfde..e420811c 100644
--- a/cmd/msgvault/cmd/sync.go
+++ b/cmd/msgvault/cmd/sync.go
@@ -174,6 +174,23 @@ Examples:
 			}
 		}
 
+		// Rebuild analytics cache if requested.
+		var cacheErr error
+		if syncRebuildCache {
+			analyticsDir := cfg.AnalyticsDir()
+			fullRebuild := false
+			if staleness := cacheNeedsBuild(dbPath, analyticsDir); staleness.FullRebuild {
+				fullRebuild = true
+			}
+			result, err := buildCache(dbPath, analyticsDir, fullRebuild)
+			if err != nil {
+				cacheErr = err
+				fmt.Printf("\nCache rebuild failed: %v\n", err)
+			} else if !result.Skipped {
+				logger.Info("cache build completed", "exported", result.ExportedCount)
+			}
+		}
+
 		if len(syncErrors) > 0 {
 			fmt.Println()
 			fmt.Println("Errors:")
@@ -183,6 +200,9 @@ Examples:
 			return fmt.Errorf("%d account(s) failed to sync: %s",
 				len(syncErrors), strings.Join(syncErrors, "; "))
 		}
+		if cacheErr != nil {
+			return fmt.Errorf("cache rebuild failed: %w", cacheErr)
+		}
 
 		return nil
 	},
@@ -264,6 +284,9 @@ func runIncrementalSync(ctx context.Context, s *store.Store, getOAuthMgr func(st
 	return nil
 }
 
+var syncRebuildCache bool
+
 func init() {
+	syncIncrementalCmd.Flags().BoolVar(&syncRebuildCache, "rebuild-cache", false, "Rebuild analytics cache after sync")
 	rootCmd.AddCommand(syncIncrementalCmd)
 }
diff --git a/cmd/msgvault/cmd/syncfull.go b/cmd/msgvault/cmd/syncfull.go
index 15847e62..95038946 100644
--- a/cmd/msgvault/cmd/syncfull.go
+++ b/cmd/msgvault/cmd/syncfull.go
@@ -166,6 +166,23 @@ Examples:
 			}
 		}
 
+		// Rebuild analytics cache if requested.
+		var cacheErr error
+		if syncFullRebuildCache {
+			analyticsDir := cfg.AnalyticsDir()
+			fullRebuild := false
+			if staleness := cacheNeedsBuild(dbPath, analyticsDir); staleness.FullRebuild {
+				fullRebuild = true
+			}
+			result, err := buildCache(dbPath, analyticsDir, fullRebuild)
+			if err != nil {
+				cacheErr = err
+				fmt.Printf("\nCache rebuild failed: %v\n", err)
+			} else if !result.Skipped {
+				logger.Info("cache build completed", "exported", result.ExportedCount)
+			}
+		}
+
 		if len(syncErrors) > 0 {
 			fmt.Println()
 			fmt.Println("Errors:")
@@ -175,6 +192,9 @@ Examples:
 			return fmt.Errorf("%d account(s) failed to sync: %s",
 				len(syncErrors), strings.Join(syncErrors, "; "))
 		}
+		if cacheErr != nil {
+			return fmt.Errorf("cache rebuild failed: %w", cacheErr)
+		}
 
 		return nil
 	},
@@ -422,11 +442,14 @@ func formatDuration(d time.Duration) string {
 	return fmt.Sprintf("%ds", s)
 }
 
+var syncFullRebuildCache bool
+
 func init() {
 	syncFullCmd.Flags().StringVar(&syncQuery, "query", "", "Gmail search query")
 	syncFullCmd.Flags().BoolVar(&syncNoResume, "noresume", false, "Force fresh sync (don't resume)")
 	syncFullCmd.Flags().StringVar(&syncBefore, "before", "", "Only messages before this date (YYYY-MM-DD)")
 	syncFullCmd.Flags().StringVar(&syncAfter, "after", "", "Only messages after this date (YYYY-MM-DD)")
 	syncFullCmd.Flags().IntVar(&syncLimit, "limit", 0, "Limit number of messages (for testing)")
+	syncFullCmd.Flags().BoolVar(&syncFullRebuildCache, "rebuild-cache", false, "Rebuild analytics cache after sync")
 	rootCmd.AddCommand(syncFullCmd)
 }
diff --git a/internal/sync/incremental.go b/internal/sync/incremental.go
index 2517f2d9..d85577bf 100644
--- a/internal/sync/incremental.go
+++ b/internal/sync/incremental.go
@@ -159,6 +159,7 @@ func (s *Syncer) Incremental(ctx context.Context, source *store.Source) (summary
 			} else {
 				for i, raw := range rawMessages {
 					if raw == nil {
+						s.logger.Warn("failed to fetch message (nil response)", "id", newMsgIDs[i])
 						checkpoint.ErrorsCount++
 						continue
 					}
diff --git a/internal/sync/sync.go b/internal/sync/sync.go
index 15cf307a..d46f7c51 100644
--- a/internal/sync/sync.go
+++ b/internal/sync/sync.go
@@ -191,6 +191,7 @@ func (s *Syncer) processBatch(ctx context.Context, sourceID int64, listResp *gma
 
 		for i, raw := range rawMessages {
 			if raw == nil {
+				s.logger.Warn("failed to fetch message (nil response)", "id", newIDs[i])
 				checkpoint.ErrorsCount++
 				continue
 			}