diff --git a/internal/report/snapshots.go b/internal/report/snapshots.go
index cfd707c..ef07593 100644
--- a/internal/report/snapshots.go
+++ b/internal/report/snapshots.go
@@ -1118,37 +1118,84 @@ func buildHourlyTotals(ctx context.Context, logger *slog.Logger, dbConn *sqlx.DB
 		startExpr := `CASE WHEN "CreationTime" IS NOT NULL AND "CreationTime" > 0 AND "CreationTime" > ? THEN "CreationTime" ELSE ? END`
 		endExpr := `CASE WHEN "DeletionTime" IS NOT NULL AND "DeletionTime" > 0 AND "DeletionTime" < ? THEN "DeletionTime" ELSE ? END`
 		overlapExpr := fmt.Sprintf(`CASE WHEN %s > %s THEN (CAST((%s - %s) AS REAL) / ?) ELSE 0 END`, endExpr, startExpr, endExpr, startExpr)
+		idExpr := `COALESCE(NULLIF("VmId", ''), NULLIF("VmUuid", ''), NULLIF("Name", ''), 'unknown')`
+		vmKeyExpr := fmt.Sprintf(`(%s || '|' || COALESCE("Vcenter", ''))`, idExpr)
 		query := fmt.Sprintf(`
-SELECT
-  COUNT(DISTINCT "VmId") AS vm_count,
-  COALESCE(SUM(CASE WHEN "VcpuCount" IS NOT NULL THEN "VcpuCount" ELSE 0 END), 0) AS vcpu_total,
-  COALESCE(SUM(CASE WHEN "RamGB" IS NOT NULL THEN "RamGB" ELSE 0 END), 0) AS ram_total,
-  COALESCE(SUM(presence), 0) AS presence_ratio,
-  COALESCE(SUM(CASE WHEN pool = 'tin' THEN presence ELSE 0 END), 0) AS tin_total,
-  COALESCE(SUM(CASE WHEN pool = 'bronze' THEN presence ELSE 0 END), 0) AS bronze_total,
-  COALESCE(SUM(CASE WHEN pool = 'silver' THEN presence ELSE 0 END), 0) AS silver_total,
-  COALESCE(SUM(CASE WHEN pool = 'gold' THEN presence ELSE 0 END), 0) AS gold_total
-FROM (
+WITH base AS (
   SELECT
+    %s AS vm_key,
     "VmId",
+    "VmUuid",
+    "Name",
     "VcpuCount",
     "RamGB",
     LOWER(COALESCE("ResourcePool", '')) AS pool,
     %s AS presence
   FROM %s
   WHERE %s
-) t
-`, overlapExpr, record.TableName, templateExclusionFilter())
+),
+agg AS (
+  SELECT
+    vm_key,
+    MAX("VcpuCount") AS "VcpuCount",
+    MAX("RamGB") AS "RamGB",
+    MAX(pool) AS pool,
+    MAX(presence) AS presence
+  FROM base
+  GROUP BY vm_key
+),
+diag AS (
+  SELECT
+    COUNT(*) AS row_count,
+    COUNT(DISTINCT vm_key) AS distinct_keys,
+    COALESCE(SUM(CASE WHEN vm_key LIKE 'unknown|%%' THEN 1 ELSE 0 END), 0) AS unknown_keys,
+    COALESCE(SUM(CASE WHEN "VmId" IS NULL OR "VmId" = '' THEN 1 ELSE 0 END), 0) AS missing_vm_id,
+    COALESCE(SUM(CASE WHEN "VmUuid" IS NULL OR "VmUuid" = '' THEN 1 ELSE 0 END), 0) AS missing_vm_uuid,
+    COALESCE(SUM(CASE WHEN "Name" IS NULL OR "Name" = '' THEN 1 ELSE 0 END), 0) AS missing_name,
+    COALESCE(SUM(CASE WHEN presence > 1 THEN 1 ELSE 0 END), 0) AS presence_over_one,
+    COALESCE(SUM(CASE WHEN presence < 0 THEN 1 ELSE 0 END), 0) AS presence_under_zero,
+    COALESCE(SUM(presence), 0) AS base_presence_sum
+  FROM base
+)
+SELECT
+  (SELECT COUNT(*) FROM agg) AS vm_count,
+  (SELECT COALESCE(SUM(CASE WHEN "VcpuCount" IS NOT NULL THEN "VcpuCount" ELSE 0 END), 0) FROM agg) AS vcpu_total,
+  (SELECT COALESCE(SUM(CASE WHEN "RamGB" IS NOT NULL THEN "RamGB" ELSE 0 END), 0) FROM agg) AS ram_total,
+  (SELECT COALESCE(SUM(presence), 0) FROM agg) AS presence_ratio,
+  (SELECT COALESCE(SUM(CASE WHEN pool = 'tin' THEN presence ELSE 0 END), 0) FROM agg) AS tin_total,
+  (SELECT COALESCE(SUM(CASE WHEN pool = 'bronze' THEN presence ELSE 0 END), 0) FROM agg) AS bronze_total,
+  (SELECT COALESCE(SUM(CASE WHEN pool = 'silver' THEN presence ELSE 0 END), 0) FROM agg) AS silver_total,
+  (SELECT COALESCE(SUM(CASE WHEN pool = 'gold' THEN presence ELSE 0 END), 0) FROM agg) AS gold_total,
+  diag.row_count,
+  diag.distinct_keys,
+  diag.unknown_keys,
+  diag.missing_vm_id,
+  diag.missing_vm_uuid,
+  diag.missing_name,
+  diag.presence_over_one,
+  diag.presence_under_zero,
+  diag.base_presence_sum
+FROM diag
+`, vmKeyExpr, overlapExpr, record.TableName, templateExclusionFilter())
 		query = dbConn.Rebind(query)
 		var row struct {
-			VmCount       int64   `db:"vm_count"`
-			VcpuTotal     int64   `db:"vcpu_total"`
-			RamTotal      int64   `db:"ram_total"`
-			PresenceRatio float64 `db:"presence_ratio"`
-			TinTotal      float64 `db:"tin_total"`
-			BronzeTotal   float64 `db:"bronze_total"`
-			SilverTotal   float64 `db:"silver_total"`
-			GoldTotal     float64 `db:"gold_total"`
+			VmCount          int64   `db:"vm_count"`
+			VcpuTotal        int64   `db:"vcpu_total"`
+			RamTotal         int64   `db:"ram_total"`
+			PresenceRatio    float64 `db:"presence_ratio"`
+			TinTotal         float64 `db:"tin_total"`
+			BronzeTotal      float64 `db:"bronze_total"`
+			SilverTotal      float64 `db:"silver_total"`
+			GoldTotal        float64 `db:"gold_total"`
+			RowCount         int64   `db:"row_count"`
+			DistinctKeys     int64   `db:"distinct_keys"`
+			UnknownKeys      int64   `db:"unknown_keys"`
+			MissingVmID      int64   `db:"missing_vm_id"`
+			MissingVmUUID    int64   `db:"missing_vm_uuid"`
+			MissingName      int64   `db:"missing_name"`
+			PresenceOverOne  int64   `db:"presence_over_one"`
+			PresenceUnderZero int64  `db:"presence_under_zero"`
+			BasePresenceSum  float64 `db:"base_presence_sum"`
 		}
 		args := []interface{}{
 			hourEndUnix, hourEndUnix,
@@ -1160,6 +1207,24 @@ FROM (
 		if err := dbConn.GetContext(ctx, &row, query, args...); err != nil {
 			return nil, err
 		}
+		duplicateRows := row.RowCount - row.DistinctKeys
+		logger.Debug(
+			"hourly totals snapshot diagnostics",
+			"table", record.TableName,
+			"hour_start", hourStart.Format("2006-01-02 15:00"),
+			"row_count", row.RowCount,
+			"distinct_keys", row.DistinctKeys,
+			"duplicate_rows", duplicateRows,
+			"unknown_keys", row.UnknownKeys,
+			"missing_vm_id", row.MissingVmID,
+			"missing_vm_uuid", row.MissingVmUUID,
+			"missing_name", row.MissingName,
+			"presence_over_one", row.PresenceOverOne,
+			"presence_under_zero", row.PresenceUnderZero,
+			"base_presence_sum", row.BasePresenceSum,
+			"presence_ratio", row.PresenceRatio,
+			"vm_count", row.VmCount,
+		)
 		hourKey := hourStartUnix
 		bucket := buckets[hourKey]
 		if bucket == nil {