diff --git a/src/cmd/compile/internal/pgo/irgraph.go b/src/cmd/compile/internal/pgo/irgraph.go
index 311f20ed81..bf11e365f1 100644
--- a/src/cmd/compile/internal/pgo/irgraph.go
+++ b/src/cmd/compile/internal/pgo/irgraph.go
@@ -217,7 +217,7 @@ func (p *Profile) processprofileGraph(g *Graph) bool {
 		// TODO(prattic): If Function.start_line is missing we could
 		// fall back to using absolute line numbers, which is better
 		// than nothing.
-		log.Fatal("PGO profile missing Function.start_line data")
+		log.Fatal("PGO profile missing Function.start_line data (Go version of profiled application too old? Go 1.20+ automatically adds this to profiles)")
 	}
 
 	return true