diff --git a/guix-data-service/jobs/load-new-guix-revision.scm b/guix-data-service/jobs/load-new-guix-revision.scm
index bd9a197..85e7edd 100644
--- a/guix-data-service/jobs/load-new-guix-revision.scm
+++ b/guix-data-service/jobs/load-new-guix-revision.scm
@@ -945,8 +945,9 @@
   (let ((missing-file-names
          (vector-fold
           (lambda (_ result file-name)
-            (if (hash-ref derivation-ids-hash-table
-                          file-name)
+            (if (and file-name
+                     (hash-ref derivation-ids-hash-table
+                               file-name))
                 result
                 (cons file-name
                       result)))