diff --git a/app/models/ci/build.rb b/app/models/ci/build.rb
index 01236b8e3c7..4a3f92ad34a 100644
--- a/app/models/ci/build.rb
+++ b/app/models/ci/build.rb
@@ -95,7 +95,7 @@ module Ci
     end
 
     def trace_html
-      trace_with_state[:html]
+      trace_with_state[:html] || ''
     end
 
     def trace_with_state(state = nil)