diff --git a/cmd/covargs/main.go b/cmd/covargs/main.go
index 4f4619c..fc3aa76 100644
--- a/cmd/covargs/main.go
+++ b/cmd/covargs/main.go
@@ -176,7 +176,7 @@
 			if ref, ok := info.ids[mod.Build]; ok {
 				moduleFiles = append(moduleFiles, ref.Filepath)
 			} else {
-				fmt.Fprintf(os.Stderr, "WARN: module with build id %s not found in ids.txt file", mod.Build)
+				fmt.Fprintf(os.Stderr, "WARN: module with build id %s not found in ids.txt file\n", mod.Build)
 				continue
 			}
 		}