diff --git a/lib/manager/resolve.js b/lib/manager/resolve.js
index 6b78f9d5cf46c48c9d5a76a6fbc570d99cbe4433..818d44d88f06eeef2fbcaf66724bc982b08a376e 100644
--- a/lib/manager/resolve.js
+++ b/lib/manager/resolve.js
@@ -14,10 +14,12 @@ module.exports = {
 };
 
 async function resolvePackageFiles(config) {
-  logger.trace({ config }, 'resolvePackageFiles()');
-  const allPackageFiles = config.packageFiles.length
-    ? config.packageFiles
-    : await manager.detectPackageFiles(config);
+  logger.debug('manager.resolvePackageFiles()');
+  logger.trace({ config });
+  const allPackageFiles =
+    config.packageFiles && config.packageFiles.length
+      ? config.packageFiles
+      : await manager.detectPackageFiles(config);
   logger.debug({ allPackageFiles }, 'allPackageFiles');
   const fileList = await platform.getFileList();
   async function resolvePackageFile(p) {