diff --git a/lib/workers/repository/cleanup.js b/lib/workers/repository/cleanup.js
index 16a9cb7eb83aae275c4a931255351ab32b5d953e..8ae52d51f01967ade5699407895bea0a624dc06a 100644
--- a/lib/workers/repository/cleanup.js
+++ b/lib/workers/repository/cleanup.js
@@ -18,15 +18,15 @@ async function pruneStaleBranches(config, branchList) {
   if (renovateBranches.indexOf('renovate/lock-file-maintenance') !== -1) {
     logger.debug('Checking lock file branch');
     const pr = await config.api.getBranchPr('renovate/lock-file-maintenance');
-    if (pr.isClosed) {
+    if (pr && pr.isClosed) {
       logger.info(
         'Deleting lock file maintenance branch as PR has been closed'
       );
       await config.api.deleteBranch('renovate/lock-file-maintenance');
-    } else if (pr.isUnmergeable) {
+    } else if (pr && pr.isUnmergeable) {
       logger.info('Deleting lock file maintenance branch as it is unmergeable');
       await config.api.deleteBranch('renovate/lock-file-maintenance');
-    } else if (pr.changed_files === 0) {
+    } else if (pr && pr.changed_files === 0) {
       logger.info(
         'Deleting lock file maintenance branch as it has no changed files'
       );