diff --git a/lib/storage/storage.go b/lib/storage/storage.go
index 3670b7ec9..74f23c318 100644
--- a/lib/storage/storage.go
+++ b/lib/storage/storage.go
@@ -1153,7 +1153,8 @@ func (s *Storage) add(rows []rawRow, mrs []MetricRow, precisionBits uint8) ([]ra
 		if mr.Timestamp < minTimestamp {
 			// Skip rows with too small timestamps outside the retention.
 			if firstWarn == nil {
-				firstWarn = fmt.Errorf("cannot insert row with too small timestamp %d outside the retention; minimum allowed timestamp is %d",
+				firstWarn = fmt.Errorf("cannot insert row with too small timestamp %d outside the retention; minimum allowed timestamp is %d; "+
+					"probably you need updating -retentionPeriod command-line flag",
 					mr.Timestamp, minTimestamp)
 			}
 			atomic.AddUint64(&s.tooSmallTimestampRows, 1)
@@ -1162,7 +1163,8 @@ func (s *Storage) add(rows []rawRow, mrs []MetricRow, precisionBits uint8) ([]ra
 		if mr.Timestamp > maxTimestamp {
 			// Skip rows with too big timestamps significantly exceeding the current time.
 			if firstWarn == nil {
-				firstWarn = fmt.Errorf("cannot insert row with too big timestamp %d exceeding the current time; maximum allowd timestamp is %d",
+				firstWarn = fmt.Errorf("cannot insert row with too big timestamp %d exceeding the current time; maximum allowd timestamp is %d; "+
+					"propbably you need updating -retentionPeriod command-line flag",
 					mr.Timestamp, maxTimestamp)
 			}
 			atomic.AddUint64(&s.tooBigTimestampRows, 1)