diff --git a/src/applications/harbormaster/storage/build/HarbormasterBuildUnitMessage.php b/src/applications/harbormaster/storage/build/HarbormasterBuildUnitMessage.php
--- a/src/applications/harbormaster/storage/build/HarbormasterBuildUnitMessage.php
+++ b/src/applications/harbormaster/storage/build/HarbormasterBuildUnitMessage.php
@@ -102,7 +102,7 @@
     $obj->setDuration((float)idx($dict, 'duration'));
 
     $path = idx($dict, 'path');
-    if (strlen($path)) {
+    if ($path !== null && strlen($path)) {
       $obj->setProperty('path', $path);
     }