diff --git a/lib/ur/usage_report.go b/lib/ur/usage_report.go
index 9b5cccddf..ce6984a4c 100644
--- a/lib/ur/usage_report.go
+++ b/lib/ur/usage_report.go
@@ -328,6 +328,11 @@ func (s *Service) reportData(ctx context.Context, urVersion int, preview bool) (
 }
 
 func (*Service) UptimeS() int {
+	// Handle nonexistent or wildly incorrect system clock.
+	// This code was written in 2023, it can't run in the past.
+	if StartTime.Year() < 2023 {
+		return 0
+	}
 	return int(time.Since(StartTime).Seconds())
 }