diff --git a/bundle_certs b/bundle_certs
index 0c21a09fbe7bd01bb98fa971911f8de79cf1a17f..948c91c2cd8ebe940a2812d4e90e7fae7a291cae 100755
--- a/bundle_certs
+++ b/bundle_certs
@@ -57,7 +57,7 @@ unbundle_cert () {
 bundle_certs () {
     for filename in "$@"
     do
-        unbundle_cert "$filename"
+        [ -f "$filename" ] && unbundle_cert "$filename"
     done
     cd certs
     issuer="$(find_root_cert *)"